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Mastocytosis is a heterogeneous disease characterized by an abnormal accumulation of mast cells (MCs) in 1 or several organs. Although a somatic KIT D816V mutation is detected in ∼85% of patients, attempts to demonstrate its oncogenic effect alone have repeatedly failed, suggesting that additional pathways are involved in MC transformation. From 3 children presenting with both Greig cephalopolysyndactyly syndrome (GCPS, Mendelian Inheritance in Man [175700]) and congenital mastocytosis, we demonstrated the involvement of the hedgehog (Hh) pathway in mastocytosis. GCPS is an extremely rare syndrome resulting from haploinsufficiency of GLI3, the major repressor of Hh family members. From these familial cases of mastocytosis, we demonstrate that the Hh pathway is barely active in normal primary MCs and is overactive in neoplastic MCs. GLI3 and KIT mutations had a synergistic, tumorigenic effect on the onset of mastocytosis in a GCPS mouse model. Finally, Hh inhibitors suppressed neoplastic MC proliferation in vitro and extend the survival time of mice with aggressive systemic mastocytosis (ASM). This work revealed, for the first time, the involvement of Hh signaling in the pathophysiology of mastocytosis and demonstrated the cooperative effects of the KIT and Hh oncogenic pathways in mice with ASM, leading to the identification of new promising therapeutic targets.

On behalf of the Lymphoma Study Association (LYSA) Introduction: Aggressive Mantle Cell Lymphoma variant (A-MCL), including blastic and pleomorphic morphological variants, is a rare subtype of MCL whose frequency varies around 10-15% of all newly-diagnosed MCL patients. According to 2017 World Health Organization (WHO) classification, the diagnosis of A-MCL is based on morphology. A high proliferation rate on Ki-67 staining is not sufficient to be classified as a blastoid or pleomorphic subtype. This might induce diagnostic confusion. The aim of the present retrospective study is to investigate whether or not the CD71, c-Myc, SOX11, P53, ki67 and P16 expressions assessed by immunohistochemistry (IHC) can distinguish A-MCL from classical MCL (C-MCL). We also investigate the prognostic value of these markers in A-MCL patients. Methods: We re-investigated all MCL patients presented with A-MCL (n=110) at diagnosis and who have been enrolled in six prospective clinical trials. At time of inclusion, a centralized pathological review was performed to confirm the diagnosis of MCL. Cases were initially classified according to the 2008 WHO classification (LYMA, MCL-SA, MCL-SJ, RIBVD and RIPAD trials) or according to the 2017 WHO classification (MCLR2-ELDERLY trials). For the present study, we performed a supplemental pathology review by a panel of 5 hematopathologists experts from the LYSA group according to 2017 WHO classification. We identified 75 cases (out of 110) of A-MCL (8 blastic and 67 pleomorphic variants) which represent 15% of all MCL enrolled in these six trials. We have compared A-MCL characteristics to C-MCL who had specimens available for TMA (n=412 C-MCL out of 487 patients enrolled). IHC was performed on TMA, using the six selected antibodies and were scored by quantifying the percentage of cells stained on each spot. Patients available for survival analysis (53 A-MCL and 312 C-MCL) were drawn from all studies (except from the MCLR2-Elderly study that is ongoing). Different cut-offs were considered for progression free survival (PFS) and overall survival (OS) for each variable. The proliferation index was evaluated with Ki67 classical determination eyeballing and Ki67 reading by grid counting. Cut-offs for each of these markers were determined using X-tile software, which determines the optimal value for classifying patients into groups based on overall and progression-free survival. Results: At baseline, the aggressive forms were similar to classical forms in terms of demographic characteristics (age at diagnosis, localization and sex). p53 protein expression was significantly higher in A-MCL patients than in C-MCL (p10%), c-MYC (>30%) Ki67 (>40%) were associated with poorer OS and PFS in the cohort of A-MCL and C-MCL patients. There was no significant difference in survival both for OS and PFS regarding P53 (>30%). In multivariate analysis stratified by trial, Ki67 by grid>40% (HR=2.303[1.479-3.585] ; p =0.0002) and c-MYC >30% (HR=1.865 [1.060-3.279] p =0.0305) were predictive for OS whereas only Ki67 by grid >40% (HR=2.055 [1.434, 2.944], p Conclusion: CD71, c-Myc, P53 and P16 expression levels assessed by IHC are higher in A-MCL as compared to C-MCL. These markers could therefore be recommended in routine practice to distinguish between A-MCL and C-MCL. We also found that patients with Ki67 count by grid >40% had significantly shorter PFS and OS and patients with high Myc expression >30% had a significantly poorer OS. Thus, MYC expression and Ki67 by IHC is a suitable test for routine diagnostic practice to assess A-MCL prognosis. Disclosures Le Gouill: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche-Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support. Ribrag:argenX: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees; Epizyme: Honoraria, Research Funding; Infinity: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; AZ: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy, Membership on an entity's Board of Directors or advisory committees. Dreyling:Novartis: Other: scientific advisory board; Celgene: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Acerta: Other: scientific advisory board; Janssen: Consultancy, Other: scientific advisory board, Research Funding, Speakers Bureau; Gilead: Consultancy, Other: scientific advisory board, Speakers Bureau; Sandoz: Other: scientific advisory board; Mundipharma: Consultancy, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: scientific advisory board, Research Funding, Speakers Bureau; Bayer: Consultancy, Other: scientific advisory board, Speakers Bureau. Hermine:Celgene: Research Funding; Novartis: Research Funding; AB science: Consultancy, Equity Ownership, Honoraria, Research Funding.

*° contributed equally to this work. Introduction: Systemic Mastocytosis (SM) is a heterogeneous disorder characterized by mast cells (MCs) accumulation in various tissues and associated with KIT mutations (KIT D816V) in more than 90% of the cases. It includes indolent (ISM) and advanced diseases (advSM), which are associated with additional molecular abnormalities. For advSM, recent clinical studies have shown that Midostaurin, a kinase inhibitor of WT and mutant KIT, induces high rate of responses associated with significant improvement of prognosis. However, complete responses are infrequent and relapses occur in a significant proportion of patients. Therefore, combination therapies are needed to increase overall response rate and prevent relapses. Venetoclax is a selective orally bioavailable BCL-2 inhibitor that induces cell death and is currently used for treatment of various lymphoid and myeloid malignancies. In an attempt to identify novel diagnostic and prognostic markers and potentially new therapeutic targets for mastocytosis, bone marrow sections of patients with different categories of mastocytosis were analyzed by IHC using anti-BCL-2 antibodies. BH-3 profiling was used to assess BH-3 proteins dependency, and sensitivity to Venetoclax alone or in combination of Midostaurin. Methods: Thirty-three adult patients were included in this preliminary study. According to the WHO classification, patients were classified as having ISM (n=10), Smoldering SM (SSM n=1), advSM (n=16, including SM-AHN (n=9), MC leukemia (MCL n=4), MC sarcoma (MCS n=2)). Most patients were KIT D816V (n=30; 90.9%); two MCL and one MCS exhibited extracellular and juxtamembrane mutations, respectively. Among these patients, 9 were treated with Midostaurin as first line therapy. Formalin fixed bone marrow sections were performed at diagnosis and during follow up. Mast cells were identified by Giemsa staining and as CD117 and tryptase positive cells. BCL-2 staining was performed by immunohistochemistry in formalin paraffin embedded fixed section. BCL-2 staining was considered as positive (>5%), heterogeneous (partial staining) or homogeneous (>80% positive cells), of high or low intensity (> or = or < to residual T cells). BH3 profiling was performed in ROSA KIT WT and ROSA KIT D816V using Cytochrome C upon exposure to distinct BH3 peptides/mimetics. Results: In ISM, BCL-2 staining was negative (n= 2/10) or when positive only in rare MCs (n=8/10), with low intensity. In contrast, all advSM cases were positive (16/16) with high (13/16), and homogeneous (6/16) staining. In MCL and MCS, BCL-2 staining was always positive with a homogeneous and high staining. In patients treated with Midostaurin, BCL-2 staining was performed before and three months after treatment initiation. Although MCs infiltration was reduced at least by 50% in all cases, number of BCL-2 positive cells and intensity of staining remain unchanged. In vitro, flow cytometry analysis showed that both MCL-like cell lines (ROSA KIT WT and ROSA KIT D816V) expressed BCL-2, MCL-1 and BCL-XL proteins. When treated with Midostaurin (200nM) for 48 hours, expression of BCL-XL and MCL-1 significantly decreased in MC lines especially the one with KIT D816V mutation. Interestingly, BCL-2 expression remained unchanged upon Midostaurin treatment, which was consistent with in vivo observations. Dynamic profiling performed in ROSA cell lines revealed that priming by midostaurin dramatically enhanced apoptotic dependencies to BCL-2 and other BH-3 proteins (>20% of apoptosis), especially in ROSA KIT D816V (figure). Conclusion: High expression of BCL-2 is associated with advSM and may participate to the pathogenesis of the disease, to its resistance to conventional chemotherapies and to partial resistance to Midostaurin. Consistent with its effect in reducing MCL-1 and BCL-XL expression, Midostaurin restored apoptotic dependency to BCL2 in human MCL-like cells, thereby suggesting that midostaurin could sensitize mast cell tumor to venetoclax. Our results provide thus a rationale to use a combination of Midostaurin and Venetoclax to treat AdvSM patients. Figure Disclosures Dubreuil: AB Science: Employment, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hermine:AB science: Consultancy, Equity Ownership, Honoraria, Research Funding; Celgene: Research Funding; Novartis: Research Funding. OffLabel Disclosure: Venetoclax preclinical studioes on mastocytosis

X-linked lymphoproliferative syndromes (XLP) are primary immunodeficiencies characterized by a particular vulnerability toward Epstein-Barr virus infection, frequently resulting in hemophagocytic lymphohistiocytosis (HLH). XLP type 1 (XLP-1) is caused by mutations in the gene SH2D1A (also named SAP), whereas mutations in the gene XIAP underlie XLP type 2 (XLP-2). Here, a comparison of the clinical phenotypes associated with XLP-1 and XLP-2 was performed in cohorts of 33 and 30 patients, respectively. HLH (XLP-1, 55%; XLP-2, 76%) and hypogammaglobulinemia (XLP-1, 67%; XLP-2, 33%) occurred in both groups. Epstein-Barr virus infection in XLP-1 and XLP-2 was the common trigger of HLH (XLP-1, 92%; XLP-2, 83%). Survival rates and mean ages at the first HLH episode did not differ for both groups, but HLH was more severe with lethal outcome in XLP-1 (XLP-1, 61%; XLP-2, 23%). Although only XLP-1 patients developed lymphomas (30%), XLP-2 patients (17%) had chronic hemorrhagic colitis as documented by histopathology. Recurrent splenomegaly often associated with cytopenia and fever was preferentially observed in XLP-2 (XLP-1, 7%; XLP-2, 87%) and probably represents minimal forms of HLH as documented by histopathology. This first phenotypic comparison of XLP subtypes should help to improve the diagnosis and the care of patients with XLP conditions.

Introduction: Follicular lymphoma (FL) is graded as 1, 2, 3A and 3B based on the number of centroblast cells. Although FL grade 3A is considered as a low-grade lymphoma, its prognostic significance compared to FL grade 1-2 remains controversial, especially for particular morphological variants with large cleaved cells or blastoid features, which are not recognized as a specific entity. Method: In order to clarify these points, FL grade 3 patients (pts) were selected from a large series of 2247 untreated pts enrolled in two LYSA trials: PRIMA (evaluating rituximab (R) maintenance after R-chemotherapy) and RELEVANCE (evaluating lenalidomide plus rituximab (R2) followed by R2 maintenance versus R-chemotherapy). FL3B pts were excluded from both trials. Sufficient material and clinical informations were available for 1757 out of 2247 pts. Among them, 161 pts including 88 of 950 PRIMA pts (9.2%) and 73 of 734 RELEVANCE pts (9.2%) were classified as FL3A. Among these FL3A cases, a panel of 7 expert hematopathologists identified 48 cases (2.7% of 1757 analyzed FL cases) which contained a significant component of large cleaved cells or medium-sized blastoid cells but did not meet grade 3B criteria. These cases were called FL3 "unclassified" (FL3U) as compared to classical FL3A (cFL3A) cases. We then analyzed the correlations between the histologic grade, phenotypic/cytogenetic features and clinical outcome. Results: FL3U were characterized by: i) proliferation of large cleaved tumor cells with moderately coarse to fine chromatin and absent or inconspicuous nucleoli (n=30) or predominance of medium-sized blastoid tumor cells with fine chromatin and small nucleoli (n=18) and ii) expression of CD20 and at least one germinal center marker. Mean of MYC and MUM1 protein expression in FL3U were 18% [from 3 to 25%] and 14.8% [3-35%], respectively, with no significant difference with cFL3A. Ki67 expression was higher in FL3U than in cFL3A (55.6% [20-90%] vs 41.3% [2-85%]) (p=0.008). Expression of p53 protein was slightly higher in FL3U than in cFL3A (37% [10-80%] vs 34.9% [8-90%] (p=0.052). FL3U had a tendency to harbor less frequent BCL2 rearrangements than cFL3A (74% vs 95%) (p=0.0620), whereas BCL6 rearrangements were significantly higher in FL3U than in cFL3A (29% vs 0%) (p=0.0034). The frequency of MYC rearrangements and 1p36 deletions in FL3U (9.6% and 6% of FL3Us, respectively) showed no significant difference with cFL3A. No detectable alteration in IRF4 locus was seen in both FL3U and cFL3A. The median age of FL3U pts was 58 years with 1:1 ratio of males to females and most pts had advanced stage at diagnosis with frequent marrow infiltration and intermediate to high FLIPI score. Outcome of pts with FL3U was not significantly different to that of cFL3A pts in Cox multivariate analyses. After a median follow-up of 117 months for PRIMA and 38 months for RELEVANCE, 89.6% of FL3U and 85.2% of cFL3A were alive with no significant difference between the 2 groups (p=0.4507). There was also no statistical difference in progression free survival (PFS) between the 2 groups (p= 0.1479). Similarly, we did not found any statistical difference in PFS between FL3U and FL1-2 and between FL1-2 and cFL3A (p=0.9210 and p=0.5375, respectively); as well as in overall survival (OS) (p=0.6223 and p=0.0960, respectively). Finally, the outcome of the whole group of FL3A pts including cFL3A and FL3U variants was similar to FL1-2 pts. Conclusion: FL grade 3A exhibits pathological and genomic diversity due to FL3U variants characterized by higher amounts of medium-sized blastoid or large cleaved cells, higher Ki67 proliferative index and p53 expression, together with increased frequency of cytogenetic BCL6 alterations and lower frequency of BCL2 rearrangements. However, in both PRIMA and RELEVANCE trials, FL3U pts showed no significant difference in terms of PFS or OS as compared to both FL1-2 and cFL3A pts. These results indicate that FL3A represents a spectrum of proliferations with variable maturity, proliferative activity and genomic alterations that may be intermediate points of progression toward FL3B/transformation. They suggest that the distinction between cFL3A and FL3U variant, as well as between FL1-2 and FL3A may not have any prognostic significance using modern rituximab- or lenalidomide-based treatments, although this has to be confirmed with different drug combinations. Disclosures Cartron: Gilead Sciences: Honoraria; Celgene: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Sanofi: Honoraria; Janssen: Honoraria. Morschhauser:Epizyme: Consultancy; Janssen: Other: Scientific Lectures; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Salles:Acerta: Honoraria; Janssen: Honoraria, Other: Advisory Board; Epizyme: Honoraria; Pfizer: Honoraria; Amgen: Honoraria; Abbvie: Honoraria; Novartis: Consultancy, Honoraria; Servier: Honoraria, Other: Advisory Board; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; BMS: Honoraria, Other: Advisory Board; Morphosys: Honoraria; Gilead: Honoraria, Other: Advisory Board; Celgene: Honoraria, Other: Advisory Board, Research Funding; Merck: Honoraria; Takeda: Honoraria; Servier: Honoraria. Xerri:Janssen: Other: Travel.

Introduction: Clinical evolution of classical Hodgkin lymphoma (cHL) cannot be always predicted by clinical, biological or radiological parameters. Given the high treatment related morbidity of clinical trials it should be interesting to get other prognostic markers to predict cHL patients evolution. Some immunohistochemical (IHC) markers have been already published as prognostic in cHL but they are still matter to debate. We have tested 13 IHC markers in the LYSA H3/4 trial of cHL which compares patients with stage III to IV cHL in a phase III who were assigned to either doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD, 8 courses) to bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisons (escBEACOPPx4 & BEACOPP x4) without radiation therapy, in order to determine if some of these markers could predict different progression free survival (PFS) or overall survival (OS). Methods: The H3/4 trial includes both high (n=549) and low risk (n=150) patients, and we obtained all biological data for 165 patients (106 high & 59 low risk). We performed 13 IHC markers (CD20, CD3, CD68, CD163, CD117, TiA1, FoxP3, ICOS, CD10, CXL13, PD1, PDL1 & EBER probe) on Tissue Micro Arrays (TMA) performed for these 165 patients. Most of these markers were evaluated on the micro-environment cells of the cHL (absolute number of cells stained when they are few or percentage of cells stained on TMA spots when they are numerous). For PDL1 and EBER, we evaluated the number of both micro-environmental cells and Reed-Sternberg (RS) cells stained with this antibody. The results of this IHC study were compared with the clinical data base of these patients. For each variable different cut-offs were studied on PFS and OS. Results: Patients characteristics were similar to those of the total population: median age (31 y), male sex (66%), nodular sclerosis histology (83.3%), stage IV (61%), B symptoms (73%), IPS>2 (66%), bulky disease (26.5%), bone marrow involvement (16%). Half of the patients received ABVD or escBEACOPP. 82.4% achieved a CR/Cru at the end of treatment and we observed 23 relapses and 14 deaths with a five-year median follow up. IHC study revealed a marked expression of tumor associated macrophages (TAM) and lymphocytes markers but none of them were associated with PFS or OS by statistical evaluation. By contrast, we found that a low count of TiA1+ cells in cHL microenvironment (median ≤29)) and a high number of RS cells PDL1+ (=100)) were significantly associated in a multivariate analysis with a worse PFS (TiA1: HR;95% CI=5.33; [1.62;17.52] and PDL1: HR;95%CI = 5.01; [1.39;18.05]). We also found that the association of a higher number of PDL1 RS+ and TAM CD68+ was statistically significant in patients of the high group risk in multivariate analysis. EBER expression on RS cells or on micro-environmental cells was not statistically associated with PFS or OS. But, the association of a higher number of EBER RS+ cells and TAM CD68+ was statistically significant in both high or low risk groups. The association of EBER and CD68 on micro-environmental cells was not statistically significant. Conclusion: In this large and unselected series of advanced cHL, we do not find prognostic significance of TAM CD68/CD163+ nor of other lymphoid markers tested nor of EBER expression. But, we showed that a low count of TiA+ cells in the micro-environment of cHL and a high level of PDL1 RS+ cells expression cells are predictive of a worse PFS in this study. We found also that there is a significant association between the number of PDL1 RS+ cells and TAM CD68+ in the high risk group and between EBER RS+ and TAM CD68+ cells in both groups. These results suggest that IHC markers could be helpful to predict evolution in cHL patients. Disclosures Casasnovas: Roche: Consultancy; takeda: Consultancy; merck: Consultancy; MSD: Consultancy; Gilead Sciences: Consultancy; Janssen: Consultancy; Roche: Research Funding; Gilead Sciences: Research Funding; Roche: Honoraria; Takeda: Honoraria; Merck: Honoraria; MSD: Honoraria; Gilead Sciences: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Coiffier:NOVARTIS: Membership on an entity's Board of Directors or advisory committees; CELGENE: Consultancy, Membership on an entity's Board of Directors or advisory committees; MORPHOSYS: Membership on an entity's Board of Directors or advisory committees; MUNDIPHARMA: Membership on an entity's Board of Directors or advisory committees; CELLTRION: Membership on an entity's Board of Directors or advisory committees.

Introduction Mantle cell lymphoma (MCL) is a heterogeneous disease with a complex genetic landscape. Among genetic anomalies, alterations of several tumor suppressor genes are prognostic markers. The p16INK4A protein, encoded by CDKN2A, is known to bind and inactivate the cyclin-dependent kinase CDK4/6, blocking the phosphorylation of the retinoblastoma protein Rb and inducing cell cycle arrest. The p16INK4A and p53 overexpression are associated with poor prognosis (D. Canioni et al. ASH 2017). Here we compared the expression levels of p16INK4A and p53 in immunohistochemistry (IHC) with the profile (copy number alterations, CNAs) of the genes encoding these proteins, on diagnosis MCL lymph nodes. Results were correlated with patients' outcome in order to identify prognostic biomarkers in MCL. Methods All samples (n=86) used in the present work were collected from untreated MCL patients enrolled in the LyMa trial (S. Le Gouill et al. NEJM 2017). IHC was performed for p16INK4A and p53 protein expression assessment on formalin fixed paraffin embedded diagnostic Tissue Micro Arrays. Cut-offs for over expression of p16INK4A and p53 proteins were 10% and 30% respectively (D. Canioni et al. ASH 2016). A pan-genomic copy number analysis was performed with the Oncoscan® SNP-array on DNA extracted from the same samples. Data were compared using chi² tests. Progression free survival (PFS) and overall survival (OS) were studied by log rank test and Kaplan Meier representation. Results Patients characteristics (n=86) were similar to the whole LyMa trial population (n= 299) regarding age, gender, Ann Arbor stage and blastoid morphology. Overexpression of p16INK4A was observed in 11% of the patients and was not associated with any deletion of CDKN2A. There was a significant association between p16INK4A protein overexpression and TP53 mono-allelic deletion (38% vs 7%; p Regarding patients' outcome, early relapse or progression ( Conclusion This work shows that p16INK4A protein expression is correlated with TP53 deletion and BCL6 gain. The p16INK4A overexpression or CDKN2A double deletion could be used as prognostic biomarkers at diagnosis to predict poor response in first line treatment. Figure. Figure. Disclosures Hermine: Hybrigenics: Research Funding; Erythec: Research Funding; Novartis: Research Funding; Celgene Corporation: Research Funding; AB Science: Consultancy, Equity Ownership, Honoraria, Research Funding.

Background Mantle cell lymphoma (MCL) is a lymphoproliferative disorder characterized by the t(11;14) balanced translocation, involving on chromosome 11 the gene encoding cyclin D1, CCND1. The enhancer of IGH, on chromosome 11, induces aberrant Cyclin D1 overexpression. A few reports have shown that the CCND1 oncogene locus is a recurrently amplified region in MCL. However, the prognostic value of this copy number abnormality (CNA) is not known. The incidence and clinical impact of CCND1 CNA were investigated on diagnostic samples from patients enrolled in the first-line randomized controlled trial LyMa (S. Le Gouill et al. NEJM 2017). Patients and methods A series of 100 lymph node biopsies performed at diagnosis for patients enrolled in the LyMa trial (n=299) was selected. After DNA extraction, CNAs were investigated in these samples using the innovative Oncoscan® SNP-array technique adapted to analyze highly degraded DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues. Ninety-four samples were informative for CNAs. CCND1 gains were controlled by fluorescence in situ hybridization on interphase nuclei, following standard procedures using LSI IGH/CCND1 XT Dual color, dual fusion translocation probes (Abbott Molecular, Des Plaines, IL). Progression-free and overall survivals were calculated from the date of inclusion until relapse/death or last news and death or last news respectively. Cumulative incidence of relapse (CIR) was estimated from the date of inclusion until the date of relapse or last news Results Amplifications of a large portion of 11q, beginning at the t(11;14) breakpoint, were observed with Oncoscan® in 7 patients. All these cases with a gain of 11q13-14 (CCND1) also had a gain of the 14q32 locus (IGH) suggesting amplification of the rearranged IGH-CCND1 region of t(11;14). This was confirmed by FISH analysis which disclosed three different configurations. The first was the classical CCND1-IGH rearrangement (CCND1 on normal chromosome 11, IGH on normal chromosome 14 and two fusion signals from the t(11;14)(CCND1-IGH)). The second configuration associated CCND1-IGH fusion signals and a gain of both CCND1 and IGH signals. The third configuration was a duplication of a CCND1-IGH fusion signals (3 signals). Both in SNP and in FISH, the amplification was always identified as sub-clonal, concerning only part of the cells. In some patients, different configurations coexisted. Compared to other patients of the series, those with amplification of IGH and CCND1 regions had a higher-risk bio-MIPI (11q13-14, p=0.015; 14q32, p=0.004). Patients with large gains at 11q13-14 (CCND1 N=7) had poorer median PFS (18 months vs not reached (NR); p=0.004), OS (35 months vs NR; p=0.01) and CIR (33 months vs not NR; p=0.004). The same was observed for patients with gains at 14q32 (IGH; N=8), with significantly different median PFS (23 months vs NR; p Conclusion Gains of the IGH-CCND1 rearrangement or involved genes appear to be a potential new biomarker predictive of poor response to first line immunochemotherapy in young MCL patients. Disclosures Hermine: Novartis: Research Funding; Hybrigenics: Research Funding; AB Science: Consultancy, Equity Ownership, Honoraria, Research Funding; Erythec: Research Funding; Celgene Corporation: Research Funding.

Background. Patients with mast cell diseases may suffer from various distressing symptoms, which can be insufficiently controlled with available therapies, severely affecting quality of life. There is thus a need for new and safe treatment options for these patients. Objectives. We aimed to evaluate safety and efficacy of omalizumab administration in patients with a systemic mast cell disorder. Methods. We included 56 patients with a systemic mast cell disorder who received omalizumab treatment between January 2015 and December 2017, after a pluridisciplinary review at the French National Reference Center for Mastocytosis (CEREMAST). Results. A complete response was achieved for 1 patient (1.8%), a major response for 30 patients (53.6%) and a partial response for 12 patients (21.4%), resulting in an overall response rate of 76.8% (43/56 patients). The response was persistent at least 3 months in 33 patients (58.9%). Median time to first response was 2 months and median time to best response was 6 months. Omalizumab was dramatically effective on all superficial and general vasomotor symptoms and on most gastrointestinal or urinary symptoms, and partially effective on most neuropsychiatric symptoms (Figure 1). Safety profile was acceptable, except for one severe adverse event (cervical edema and dyspnea after the first injection of omalizumab). Side effects were reported in 16 patients (28.6%), mainly of low to mild intensity, yet causing interruption of treatment in 6 patients (10.7%). Conclusion. Omalizumab is an effective treatment option in systemic mast cell disorders, and displays a favorable safety profile. Prospective studies remain necessary to confirm these encouraging results. Disclosures No relevant conflicts of interest to declare.

Mastocytosis (M) is a clonal myeloid-disabling disorder for which no curative therapy is currently available. Cladribine (2-chlorodeoxyadenosine [2-CdA]) is a synthetic purine analog cytoreductive treatment, for which efficacy is mostly reported in advanced M. Here we report, with a long-term follow-up period (>10 years) efficacy and safety in 68 adult patients with M (36 [53%] had indolent M and 32 [47%] had advanced M) treated by 2-CdA (0.14 mg/kg in infusion or subcutaneously, days 1-5; repeated at 4-12 weeks until 1 to 9 courses). Median 2-CdA courses number was 3.7 (1-9). The overall response rate was 72% (complete remission [R]/major/partial R: 0%/47%/25%) and according to indolent/advanced M was 92% (major/partial R: 56%/36%) and 50% (major/partial R: 37.5%/12.5%), respectively. Clinical improvement was observed for 10 of 11 mediator release and 6 of 7 mast cell infiltration-related symptoms including urticaria pigmentosa and organomegaly (P < .02). Serum tryptase levels decreased (P = .01). Median durations of response were 3.71 (0.1-8) and 2.47 (0.5-8.6) years for indolent and aggressive M, respectively. The most frequent grade 3/4 toxicities were lymphopenia (82%), neutropenia (47%), and opportunistic infections (13%). 2-CdA appears to provide a significant efficacy with some toxicity in various M subtypes, mostly in indolent M, refractory to multiple symptomatic therapies.

Mantle cell lymphoma (MCL) accounts for approximately 6% of non-Hodgkin's Lymphoma (NHL) in adults. MCL commonly responds to initial therapy but inevitably patients relapse and response duration decreases from one salvage therapy to the next. Indeed, there is an urgent need to control and/or eradicate residual MCL cells that are responsible for early and late relapses. Maintenance with Rituximab (RM) after R-CHOP has been shown to prolong OS in elderly MCL patients treated with R-CHOP (Kluin-Nelemans et al. NEJM). Induction with high-dose cytarabine followed by autologous stem cell transplant (ASCT) consolidation is standard of care for young patients but RM after ASCT has never been investigated so far. The LyMa trial (ClinicalTrials.gov, NCT00921414) is a prospective international randomized phase III trial that investigated RM after ASCT in young previously untreated MCL patients. Patients were included at diagnosis (I, untreated, diagnosis of MCL according to WHO 2008 classification). Induction immuno-chemotherapy consisted of 4 courses of R-DHAP every 21 days (Rituximab, Dexamethasone, High-dose cytarabine, salt Platinum) followed by ASCT consolidation. Patients who were not in response (CR/CRu or PR) after R-DHAP received 4 additional courses of R-CHOP-14 before ASCT. The conditioning regimen for ASCT was R-BEAM. Patients in response after ASCT were randomized (1:1) between RM or no RM. RM consisted of one infusion of Rituximab (375mg/m2) every 2 months for 3 years. The primary endpoint was event-free survival (EFS) calculated from time of randomization; events were defined as disease progression, relapse, death, severe infection or allergy to Rituximab. Progression-free survival (PFS) and overall survival (OS) from time of diagnosis and time of randomization were secondary endpoints. The interim analysis showed a trend for a longer EFS and PFS in favor of RM arm. (Le Gouill et al, ASH 2014, abs 146). Herein, we present the results of the final analysis. RESULTS. Two hundred and ninety nine patients were enrolled from September 2008 to August 2012. Demographic and clinical characteristics of the patients were as followed: median age of 57y (27-65), 79% of male, MIPI-low in 53.2%, MIPI-I in 27.4% and MIPI-H in 19.4%. After inclusion, 277 patients completed the 4 courses of R-DHAP. The CR/CRu rate after R-DHAP was 77.3% and ORR was 89.3%. Twenty patients received R-CHOP. In all, 257 patients (including 12 patients who received R-DHAP/R-CHOP) underwent ASCT. After ASCT, 240 patients were randomized (RM, n=120; no RM, n=120). Median follow-up (mFU) from inclusion and from randomization were 54.4m (52.7-59.2) and 50.2m (46.5-54.2), respectively. The mPFS and mOS from inclusion in an intention to treat analysis were not reached; the 4y-PFS and OS were 67.8% (95%CI, 62.1 to 72.8) and 78% (95%CI; 72.8 to 82.3), respectively. According to EFS definition, 47 (39.2%) patients had an event in the no RM versus 25 (20.8%) in the RM arm. The mEFS from randomization was not reached in both arms. The 4y-EFS was 61.4% (95%CI; 51.3 to 69.9) in the no RM arm vs 78.9% (95%CI; 69.6 to 85.6) in the RM arm (p=0.0012). The EFS duration was significantly superior in the RM arm with a 54.3% reduction in the risk of event (Hazard ratio (HR)= 0.457; 95%CI, 0.28 to 0.74; p=0.0016). The median PFS and OS from randomization were not reached in both arms. The 4y-PFS and OS from randomization were superior in the RM arm: 82.2% (95%CI; 73.2 to 88.4) vs 64.6% (95%CI; 54.6 to 73) (p=0.0005) and 88.7% (95%CI; 80.7 to 93.5) vs 81.4% (95%CI; 72.3 to 87.7)(p=0.0413). Patients in the RM arm had a 60% reduction of risk of progression (HR=0.4; 95%CI, 0.23 to 0.68; p=0.0007) and a 50% reduction of risk of death (HR=0.5; 95%CI, 0.25 to 0.98; p=0.0454). The per protocol analysis yielded similar results. In conclusion, The LyMa trial demonstrates for the first time that RM after ASCT prolongs EFS, PFS and OS. Thus, 4 courses of R-DHAP plus ASCT (without TBI) followed by RM maintenance (one infusion every 2 month for 3 years) is a new standard of care for young MCL patients. Disclosures Thieblemont: Gilead: Consultancy; Roche: Consultancy; Janssen: Consultancy. Ribrag:Pharmamar: Membership on an entity's Board of Directors or advisory committees; Esai: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; NanoString: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Infinity: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; ArgenX: Research Funding. Casasnovas:BMS: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding; ROCHE: Consultancy, Honoraria, Research Funding. Haioun:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hermine:Celgene: Research Funding; AB science: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding, Speakers Bureau; Novartis: Research Funding; Alexion: Research Funding.

Introduction: Prognosis markers available at diagnosis are needed to discriminate high-risk (HR) from low-risk (LR) mantle cell lymphoma (MCL) patients (Delfau-Larue et al. Blood 2005; Balasubramanian et al. ASH 2014 abstract 78). In the present work, we report a whole-genome copy number analysis performed with a new technical approach. Samples from ninety-six young MCL patients treated in the phase III LyMa trial (Le Gouill et al. ASH 2014) have been investigated. Methods: Samples were selected according to material availability and patient's outcome. The cohort included 9 HR patients with primary refractory disease or relapse within one year post-diagnosis and 87 patients still in response one year after diagnosis, including 64 LR patients who were still in complete remission more than 30 months after diagnosis. Lymph node biopsies collected at diagnosis, formalin-fixed and paraffin-embedded were used to extract DNA, even when highly degraded. Both whole-genome copy number profiling and the most frequent somatic mutations of TP53 were analyzed with 50 ng of genomic DNA using the OncoScan® FFPE Assay, a new robust and validated single nucleotide polymorphism (SNP) array (Foster et al. BMC Med Genomics 2015). This assay uses the Molecular Inversion Probe technology (MIP) optimized for highly degraded FFPE samples. The ~200000 probes allowed for the detection of genome-wide copy number alterations (CNAs) with a higher concentration in cancer-related genes. The frequency and prognosis impact of CNAs were evaluated. Results and discussion: Overall, 68 recurrently altered regions were observed in 98% of patients. Deletions were more frequent than amplifications, at 9 vs 3 by patient respectively. Recurrent CNAs included losses at 1p21 (43%), 11q22 (ATM) (40%), 13q14 (24%), 9q22-31 (CDKN2A/CDKN2B) (25%), 13q33-34 (RB1) (21%), 8p11 (18%), 17p13 (TP53) (17%) and gains at 3q26-27 (35%), 3q21 (27%), 10q11 (13%) 15q11 (13%), 11q13 (CCND1) (12%), 13q31 (mir-17-92) (11%), 7p22 (CARD11) (10%), 10p12 (BMI1) (9%), 8q24 (MYC) (8%) and 12q13 (CDK4) (7%). TP53 mutations were detected in 5 patients including two with 17p13 deletion and showed a trend to be more frequent in the HR group vs LR (22% vs 3%; p=0.07). Deletions of TP53 (44% vs 14%; p=0.04), CDKN2A (67% vs 29%; p=0.054) and 8p11 (89% vs 24%; p=0.0002) were more frequent in the HR. The CDK4 (33% vs 6%; p=0.03) and mir-17-92 (44% vs 9%; p=0.01) loci were more frequently amplified in HR patients. Amplification of the miR-17-92 locus could explain why miR-17-92 overexpression, a PI3K/AKT pathway regulator, was associated with a worse prognosis in MCL (Roisman et al. Genes Chromosomes Cancer 2016). In contrast, amplification of the CARD11 locus was associated with LR (16% vs 0%; p=0.03). Conclusion: This study confirms the poor prognostic impact of TP53 alterations and reveals new CNAs associated with HR MCL such as 8p11 deletion and mir-17-92 locus amplification. Conversely CARD11 amplification appears to be associated with LR and absent from HR patients. These findings provide important clues for future theranostic-driven therapies in MCL. Disclosures Hermine: Alexion: Research Funding; Novartis: Research Funding; Celgene: Research Funding; AB science: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding, Speakers Bureau.

The frequent occurrence of BCL2-IgH rearrangements in follicular lymphoma (FL) makes detection of low numbers of tumor cells possible by polymerase chain reaction (PCR). The presence of BCL2-IgH in the bone marrow (BM) and peripheral blood of many FL patients at the time of autografting has led to the suggestion that selection of the CD34- enriched fraction may lead to reinfusion of lower numbers of tumor cells. To address this issue, we PCR-amplified BCL2-IgH from fluorescence-activated cell sorting (FACS)-purified BM CD34+ and CD34- fractions in seven FL patients showing a PCR-detectable translocation in the major breakpoint region of BCL2, five of which showed morphological BM involvement. The total CD34+ fraction showed diminished but residual positivity in the first two cases tested. Therefore, BM cells from the remaining five patients were sorted for the CD34+19- immature population, the CD34+19+ B-cell precursors, and the CD34–19+ mature B-cell fraction. The CD34+19- subpopulation was negative in four of five, despite evident BM infiltration in three cases. In contrast, the CD34+19+ fraction was positive in all three cases tested. These cells represented 0% to 50% (mean, 18%) of the total CD34+ population, suggesting that, if reinfusion of BCL2-IgH- positive cells plays a role in postautograft relapse in FL, therapeutic CD34 selection procedures should include additional purging of the CD34+19+ B-cell precursors or, at least, assessment of the proportion of CD19+ cells in the CD34+ fraction and its correlation with clinical outcome postreinfusion.

Histiocytoses are rare disorders of unknown origin with highly heterogeneous prognosis. BRAF mutations have been observed in Langerhans cell histiocytosis (LCH). We investigated the frequency of BRAF mutations in several types of histiocytoses. Histology from 127 patients with histiocytoses were reviewed. Detection of BRAFV600 mutations was performed by pyrosequencing of DNA extracted from paraffin embedded samples. Diagnoses of Erdheim-Chester disease (ECD), LCH, Rosai-Dorfman disease, juvenile xanthogranuloma, histiocytic sarcoma, xanthoma disseminatum, interdigitating dendritic cell sarcoma, and necrobiotic xanthogranuloma were performed in 46, 39, 23, 12, 3, 2, 1, and 1 patients, respectively. BRAF status was obtained in 93 cases. BRAFV600E mutations were detected in 13 of 24 (54%) ECD, 11 of 29 (38%) LCH, and none of the other histiocytoses. Four patients with ECD died of disease. The high frequency of BRAFV600E in LCH and ECD suggests a common origin of these diseases. Treatment with vemurafenib should be investigated in patients with malignant BRAFV600E histiocytosis.

Hepatitis C virus (HCV) infection is a well-established risk factor for the development of B cell non-Hodgkin lymphoma (B-NHL). Two main pathways have been proposed to explain the role of the virus in lymphomagenesis: 1) transformation of B cells either directly by oncogenic viral proteins, or by a hit-and-run mechanism inducing a mutator phenotype, and 2) chronic antigenic stimulation through the B cell receptor (BcR) in conjunction to the binding of the viral E2 protein to its receptor CD81. There are however conflicting data regarding whether the BcR of the lymphomatous cells are capable of directly recognizing viral proteins or, rather, they possess a rheumatoid factor (RF) activity, binding instead polyclonal immunoglobulin (IG) within immune complexes trapping the virus. To further elucidate the role of antigenic stimulation in the natural history of HCV-associated B-NHL, we analyzed the IG gene repertoire of both heavy and light chains expressed by neoplastic cells in 41 cases of HCV-associated NHL, including: 29 marginal zone lymphoma (MZL); 7 diffuse large B-cell lymphoma (DLBCL) of which 3 originated from transformed MZL ; and 5 other low-grade B-cell NHL. Tumor cells were obtained from blood in 39 cases, bone marrow and a lymph node biopsy in 1 case each. Forty-three productive IGHV-IGHD-IGHJ gene rearrangements were obtained, which displayed a clear biased gene composition as 3 IGHV genes contributed to almost half of the repertoire: IGHV1-69 (11/43, 25,6%), IGHV3-7 (5/43, 11.6%), IGHV3-21 (4/43, 9.3%). This was also true for both IGHD genes (IGHD3-22: 12/43, 27.9%), and IGHJ genes (IGHJ4: 17/43, 39.5%; IGHJ3: 17/43, 25.6%). All but 3 sequences carried somatic hypermutations (SHM) in their IGHV genes with a median identity to the germline of 97.6% (range 86.5-100%). Thirty-eight productive IG light chain rearrangement sequences were obtained from 36 cases, of which 30 (78.9%) were IGK. Similarly, they exhibited strong gene usage bias with an over-representation of IGKV3-20 (9/30, 30%), as well as IGKJ1 (11/30, 33.3%) and IGKJ2 (6/30, 20%). IG light chain sequences were found to harbor similar SHM load with a 97% median identity to germline (range 91-100%). As previously described, we observed preferential pairing of heavy and light chain genes, with 6 of the 9 IGHV1-69 cases (with available light chain sequence data) being associated with IGKV3-20. Using established criteria, we found 5 cases (11.6%) carrying stereotyped BcR i.e. IGHV-IGHD-IGHJ gene rearrangements with quasi-identical amino-acid (AA) sequences, including the highly variable complementary determining region 3 (CDR3). Three cases concerned IGHV3-7/IGHD3-22/IGHJ3 rearrangements with an 18 AA-long CDR3, and 2 concerned IGHV1-69/IGHD3-22/IGHJ4 rearrangements with a 13 AA-long CDR3. Identity within the CDR3 extended to AA encoded by randomly inserted N-region nucleotides. We failed to establish correlations between histological categories and IG repertoire, probably due to the uneven distribution of lymphoma subtypes within our cohort. In contrast, most if not all sequences with biased IG gene usage, including the 5 stereotyped BcR ones, were found amongst the 28/41 cases (68.3%) with mixed cryoglobulinemia type II and/or positive for RF (MC/RF+). These two categories of patients differed also regarding the SHM load of their IGHV genes since MC/RF+ cases were signlificantly less mutated than MC/RF- cases (median identity to germline: 97.9% vs 95.9%, p= 0.048). We then searched for similar sequences in public databases and collaborative studies. Stereotyped BcR sequences similar to those of our cases were detected in HCV-associated lymphoma, but also in other HCV-negative B-cell maligancies e.g. MALT lymphoma (some associated with RF) and chronic lymphocytic leukemia, non malignant B cells with RF activity, and non malignant marginal zone splenic B cells. Sequence similarity extended to some shared AA replacements, e.g. identical AA introduced by HSM at the same positions. In conclusion we confirm the highly biased IG repertoire of HCV-associated lymphoma. However this feature seems to be linked essentially to the presence of a MC and/or RF. As quasi-identical sequences are found in HCV-negative malignant and normal B cells, our data support the hypothesis that HCV-associated lymphomatous cells originate from precursors endowed with auto-immune properties rather than B cells expressing an anti-virus BcR. Disclosures Stamatopoulos: Gilead Sciences: Research Funding; Janssen Pharmaceuticals: Research Funding.

Introduction Diffuse Large B Cell Lymphoma (DLBCL) is the most common lymphoid malignancy, accounting for 30-40% of all Non Hodgkin Lymphomas. Gene expression profiling (GEP) has identified three main subtypes of DLBCL: Germinal Center B-cell like (GCB), Activated B-Cell like (ABC) and Primary Mediastinal B-cell Lymphoma (PMBL). Recently, Next Generation Sequencing (NGS) has enabled a more detailed characterization of DLBCL mutational profiles. Conventional techniques such as immunohistochemistry (IHC) and FISH are also widely used to describe DLBCL. However, no study has yet performed an integrative analysis of the mutational, gene expression, IHC and FISH profiles of DLBCL, in order to provide a comprehensive view of this disease. Methods 215 patients with de novo DLBCL in the prospective, multicenter and randomized LNH-03B clinical trials led by the LYmphoma Study Association (LYSA) were included in this study. Microarray-based GEP identified 81 ABC, 83 GCB, 18 PMBL and 33 other. Mutational profiles of patients' tumor DNA were established using Lymphopanel NGS, designed to identify mutations in 34 genes important for lymphomagenesis. For each recurrently mutated gene, we applied ROMER (Ritchie, Nucleic Acids Res, 2015) to perform gene set enrichment analysis on differential expression profiles of mutant and wild-type patients, using a multifactorial model accounting for subtype. The gene sets were obtained from the MSIGDB Hallmarks (Subramanian A, PNAS, 2005) and Signaturedb (Schaffer, Immunol Rev, 2006) collections. When possible, IHC was performed for IgM (n=150), MYC (n=140), BCL2 (n=148), BCL6 (n=146), CD10 (n=152), FOXP1 (n=147) and MUM1 (n=152); FISH was performed for MYC (n=131), BCL2 (n=133) and BCL6 (n=131). Results As expected, EZH2 mutations were significantly associated with upregulation of GCB gene expression (p An association between BCL6 translocations and ABC subtype was confirmed, via a correlation with ABC-enriched CD79B mutations (p=0.02), although interestingly not with MYD88 mutations. MYD88 mutations were correlated with an upregulation of genes involved in proliferation or repressed by PRDM1 (FDR=0.04 each), as well as with an upregulation of genes involved in checkpoint controls, such as E2F targets and genes involved in DNA repair (FDR=0.03 each). All MYD88 mutants expressed FOXP1 in IHC (p PMBL-enriched mutations in our cohort were frequently associated with IgM and FoxP1 negative IHC, as expected (WHO 2008 and Roschewski, Nat Rev Clin Onc). XPO1 and ITPKB mutations were correlated with JAK-STAT pathway activation in the total cohort, including upregulation of interferon-inducible genes for both gene mutations (FDR=0.02 and FDR=0.08 respectively) and upregulation of BCL6-repressed genes for XPO1 mutations only (FDR=0.02). Interestingly, CD58 mutations were significantly correlated with upregulation of Nfkb pathway target genes (FDR=0.06), perhaps due to their negative impact on CD2 activation and ROS production inhibition. Conclusion The results herein provide steps toward a comprehensive, multi-level overview of DLBCL. We highlight differential gene set expression linked to gene mutation status, as well as driver translocation-associated mutational profiles. By using an integrative analysis approach, this study broadens our understanding of DLBCL subtypes' diverse genetic backgrounds. Disclosures Briere: St. Louis Hospital, Paris, France: Employment. Salles:Celgene Corporation; Roche: Speakers Bureau; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche and Gilead Sciences: Research Funding.

Inherited deficiency of major histocompatibility complex (MHC) class II molecules impairs antigen presentation to CD4+ T cells and results in combined immunodeficiency (CID). Autosomal-recessive mutations in the RFXANK gene account for two-thirds of all cases of MHC class II deficiency. We describe here the genetic, clinical, and immunologic features of 35 patients from 30 unrelated kindreds from North Africa sharing the same RFXANK founder mutation, a 26-bp deletion called I5E6-25_I5E6 + 1), and date the founder event responsible for this mutation in this population to approximately 2250 years ago (95% confidence interval [CI]: 1750-3025 years). Ten of the 23 patients who underwent hematopoietic stem cell transplantation (HSCT) were cured, with the recovery of almost normal immune functions. Five of the patients from this cohort who did not undergo HSCT had a poor prognosis and eventually died (at ages of 1-17 years). However, 7 patients who did not undergo HSCT (at ages of 6-32 years) are still alive on Ig treatment and antibiotic prophylaxis. RFXANK deficiency is a severe, often fatal CID for which HSCT is the only curative treatment. However, some patients may survive for relatively long periods if multiple prophylactic measures are implemented.

Introduction Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder associated with mutations in the ATMgene and characterized by cerebellar ataxia, telangiectasia, immune defect, and a high incidence of lymphoid and solid cancers. We conducted a retrospective study of the patients with AT enrolled in the registry of the French National Reference Center for Primary Immune Deficiencies, in order to describe the incidence, subtypes, and outcomes of cancer and mainly of lymphoproliferative diseases (LPD) occurring in AT. Most of the LPD of this study were centrally reviewed by 2 expert hematopathologists. Patients & Results Sixty nine patients with cancers were identified among the 279 patients with AT of our cohort. Eight patients developed carcinomas, 8 acute leukemias, 3 T-cell prolymphocytic leukemias and 50 developed lymphomas. Among the lymphomas, 12 were classical Hodgkin's lymphomas (cHL), and 38 high-grade non-Hodgkin lymphomas (NHL, 26 of B-cell type, 4 of T-cell type, and 8 not phenotyped). We obtained a centralized histopathology review in 31 cases classified by pathology reports as cHL (n=6) and high-grade NHL (n=25). Cases were reviewed according to the WHO classification by H&E staining and immunohistochemistry. The presence of EBV was analyzed using antibodies to LMP and in situ hybridization for EBER. Concordance between the diagnosis established on pathology reports and the centralized review was excellent. All 6 cases of cHL were confirmed by the pathology review. The 25 cases initially diagnosed as high-grade NHL based on pathology reports fell into several WHO classification categories. Six corresponded to Burkitt's lymphomas (BL) and 12 to diffuse large B-cell lymphomas (DLBCL). Among the latter, 10 could be further classified according to cell-of-origin by the Hans algorithm as germinal center (GC, 2) and non-GC (8). Seven cases displayed polymorphic histological features reminiscent of post-transplant lymphoproliferative disorders (LPD), 5 polymorphic B cell LPD (pLPD), 1 with features of infectious mononucleosis (IM), another with features of plasmacytic hyperplasia LPD. EBV could be evaluated in 28 cases. All 6 cHL, 4 out of 11 DLBCL, all 5 pLPD, and the case of IM-like LPD were EBV positive by LMP and/or EBER staining. The 5 cases of BL that were evaluated were all EBV negative. Median age at diagnosis was 7.8 years [range 3 – 24], 14.9 [5.8 – 17.1], 12.2 [5.4 – 29] and 11 [6.3 – 17.7] for pLPD, cHL, BL and DLBCL respectively (p=ns). Median survival after diagnosis of lymphoma was 35, 8.6, 6 and 8 months for pLPD, cHL, BL and DLBCL respectively (p=ns). ATM mutation analysis was available for 20 cases (8 hypomorphic mutations, 12 loss-of-function mutations). There were no differences in age at diagnosis of lymphoma or survival according to the ATM mutation class or the EBV status. Conclusion B-cell malignancies including cHL and B-cell NHL are the most frequent malignancies in A-T and can be further classified as DLBCL, BL and cases with polymorphic features resembling post-transplant LPD. EBV seems to be associated with all cHL, approximately 50% of DLBCL and polymorphic LPD, but not with BL. The majority of DLBCL are non-GC type by immunohistochemistry. On this series of 31 patients, ATM mutation type was not associated with differences in type of lymphoma or outcome. Disclosures No relevant conflicts of interest to declare.

[Graphic][1] INTRODUCTION Mast cell disease is a clonal haematological disorder resulting in organ infiltration by mast cells and uncontrolled degranulation (mast cell activation syndrome, MCAS). Although not characteristic and poorly explained, both primary (platelet’s adhesion and aggregation) and secondary (coagulation cascade leading to thrombin formation) clotting abnormalities are observed among some patients. METHODS We retrospectively identified patients with established diagnosis of mastocytosis and related clotting abnormalities (clinical and/or biological) using the French National Reference Centre for Mastocytosis database. RESULTS AND DISCUSSION Our cohort included 14 adult patients (median age of 42 [range 26-78] years, sex ratio 3.7, CKIT D816V in 13/14 cases, median tryptase of 200 [4-1240] ng/mL). Four patients had typical symptoms and/or clotting tests (PFA, von Willebrand’s disease [vWD] screening) indicating abnormalities of primary haemostasis [Table, patient 1], with n=1 confirmed and n=2 highly suspicious of vWD. They presented with either nil (n=1) or mild (n=3) mucocutaneous bleeding. This could be due to heparin binding to von Willebrand’s factor, therefore preventing platelet aggregation. Ten patients had abnormalities of coagulation cascade (prolonged PT, aPTT, reduced clotting factors II, V, VII, X), usually transient but with bleeding in 7 cases (severe/life-threatening in 5 of them ) [Table, patient 3]. Clotting abnormalities were typically accompanied by anaphylactoid symptoms of MCAS and increased by the presence of hematopoietic organ infiltration [Table, patients 2-4]. Haemostatic management (red blood cells and platelets transfusion, fresh frozen plasma, vitamin K, antifibrinolytic) was unsuccessful, while control of mast cell activity (e.g. with and steroids) would achieve haemostasis, indicating the crucial role of mast cell mediators. These mainly include tryptase and heparin, which inhibit the intrinsic pathway, inducing an anticoagulant state. The exact prevalence of clotting abnormalities in mastocytosis remains unclear and probably underestimated. However, we found a predominance of aggressive types of mastocytosis in the population with coagulation cascade abnormalities: 50% had aggressive systemic mastocytosis associated or not with a clonal haematological non mast cell lineage disease (ASM/AHNMD), 30% had mast cell leukaemia (MCL). All deceased patients (n=5, 36% of the overall population) belonged to this group. In contrast, mastocytosis was indolent in 75% of cases in the group with primary haemostasis abnormalities. | Patient number / gender; Diagnosis | Acute phase of MCAS | H/SMG | Bleeding | Biology | Clotting after episode | | | ------------------------------------------ | --------------------------- | -------------------- | ---------------- | --------------- | ---------------------- | ------------------ | ------------------------------------------------------------------------------------------------------------ | | PLT 150-300 | PTr ≥ 70% | aPTTr ≤ 1.20 | | | #1 / M; CM | no | no | Cutaneous | N | 89% | 1.23 | Spontaneously resolved | | | #2 / M; SSM-AHNMD† | yes | no | GI bleed | N | 37% | 1.75 | Resolved after steroids | | | yes | no | GI bleed | 20 | 62% | 1.41 | Resolved after symptomatic control of MCAS. | | #3 / M; aMCL | yes | yes | Acute SDH | 87 | 61% | 1.46 | Resolved after steroids | | #4 / M; ASM-AHNMD† | no | yes | None | 138 *14 | 62% *43% | 1.39 *1.97 | Worsening clotting alongside ASM progression and unrelated to the AHNMD. Response to steroids not assessable | | | | | | | | | | | Abstract 2856. Table: Description of 4 selected patients AHNMD: associated clonal haematological non mast cell lineage disease; aMCL: acute mast cell leukemia; aPTTr: activated partial thromboplastin time ratio; CM: cutaneous mastocytosis; H/SMG: hepato or splenomegaly; GI: gastrointestinal; ISM: indolent systemic mastocytosis; N: normal; SSM: smouldering systemic mastocytosis; PLT: platelet, in x103/µL; PTr: prothrombin time ratio; SDH: subdural haematoma. Reference values are indicated below PLT, PTr, aPTTr. †: patient deceased from the disease or complications of the latter. *6 months later. CONCLUSIONS AND PERSPECTIVES Blood coagulation abnormalities in mastocytosis appear secondary to a hyperactivity of the clonal mast cell, resulting in an anticoagulant state and typically presenting in the context of MCAS and/or significant mast cell proliferation. They are particularly prevalent in aggressive types of mastocytosis, and are only successfully controlled by mast cell inhibitors, notably steroids. More data are required to better correlate clinical and biological pictures, and to assess whether standard or specific clotting tests could be used as a marker of mast cell activity and potentially of poor prognosis in patients with systemic mastocytosis. Disclosures No relevant conflicts of interest to declare. [1]: /embed/inline-graphic-2.gif

Background Advanced Systemic Mastocytosis (adSM) still have very poor prognosis. No standard of care is yet available. Midostaurin (PKC412) is a powerful TKI inhibit of VEGFR, FLT3 and most importantly the mutated CKITD816V and D816Y. Preliminarily results from an international phase II trial (Gotlib et al., Blood 2012) reported interesting results in this subgroup of patients. We report herein on the French experience of the compassionate use of PKC412 for the treatment of adSM and compare their outcome to matched adSM historical control patients (pts) who did not receive PKC412 (control group). Methods Over a period of 12 months (from August 2012, date of PKC412 Temporary Approval for Use in France), 22 pts received PKC412 and could be analysed. PKC412 100 mg twice daily was administered orally as continuous 28-day cycles until progression or unacceptable toxicity. Pts were evaluated according to the response criteria used in the recent phase 2 trial on midostaurin (Gotlib et al.). The overall survival (OS) of these 22 patients was compared to the OS of 42 age and WHO subcategories matched control adSM patients who were treated before PKC412 era. Results 2 female and 20 male pts with a median age of 65 years [35-84] received midostaurin. Overall, 21 pts (95%) with adSM (5 ASM; 2 MCL; 1 MCS; 12 ASM-AHNMD; 1 SSM-AHNMD,1) and 1 pt progressive SSM. Median number of C-Findings was 3 (0-4). Hepato- and/or splenomegaly were present in 20 (91%) and 21 (95%) pts. Median tryptase level was 204 ng/l (85-2000). Median haemoglobin level, platelet and PMN counts were respectively 10.1g/dl (6.8-13.9), 117G/L (22-289) and 2.8G/L (0.3-17). Twenty (91%) pts had cKIT D816V mutation, 2 pts had cKITWT. ASXL1 and TET2 were mutated in 3/7 and 2/7 tested, respectively. Steroids, 2-chlorodeoxyadenosine and Interferon were administered in 9, 4 and 2 pts prior to midostaurin. After a median exposure time of 6.9 [1.6-27.5] months, the overall response rate (ORR) was 77.2% including, major responses (n=13; 59%) (incomplete major in 8 pts, pure clinical in 5); partial response (n=5, 23%) (good partial in 3, minor partial in 2). Three patients were rapidly progressive ( The control group consisted in 42 pts with a median age of 65.5 years [23-84]. There were 17 ASM-AHNMD, 21 ISM-AHNMD, 2 SSM-AHNMD, 1 CM-AHNMD and 1 MCL patients. Median tryptase level was 107ng/l [19-501]. Median haemoglobin level, platelet and PMN counts were respectively 12.1g/dl [8-15], 200G/L [10-1036] and 4.6G/L [0.5-24.3]. Thirty-three (79%) pts had cKIT D816V mutation, 7 pts were cKITWT. ASXL1 and TET2 were mutated in 6/29 (21%) and 7/29 (24%) of pts tested, respectively. Steroids, 2-CdA, interferon, imatinib, thalidomide have been used in 19, 21, 6, 4, and 6 pts respectively. Survival distributions were estimated using the adjusted Kaplan-Meier method from the date of diagnosis to the last follow-up for the PKC412 treated and the control groups. Median survival time for PKC412 treated patients was significantly longer than control patients (p=0.04). Conclusion PKC412 is active in advanced SM. Despite the absence of complete remission, PKC412 gives survival advantage for patients with adSM over pts who did not receive the drug. Disclosures No relevant conflicts of interest to declare.

Wiskott-Aldrich syndrome (WAS) is an X-linked primary immune deficiency (PID) characterized by persistent thrombocytopenia, eczema and immunodeficiency. It has been suggested that these patients had an increased risk of lymphoproliferative diseases (LPD). We conducted a retrospective study in order to describe LPD occurring in patients with WAS/XLT (X Linked Thrombocytopenia with WAS gene mutation) enrolled in the French national registry for PIDs. Post- hematopoietic stem cell transplantation (HSCT) LPD were excluded. Methodology of the French National Registry for PIDs has been previously described (Clin. Immunol, 2010, ASH 2009 abstract#23950). Eight patients (4%) with LPD were identified among the 197 patients of our cohort. All patients had a WAS and presented first symptoms of WAS before the age of one year. One patient developed a LPD before the clinical diagnosis of WAS. All patients for whom histological charts were available (6/8) developed a B-cell LPD. Three of them had diffuse large B-cell lymphomas and three patients had polymorphic B-cell LPD associated with EBV and without detection of clonal IGHV rearrangement. The median age of cancer diagnosis was 18.3 years (range: 2.0-50.7). All LPD were disseminated diseases, mostly with a central nervous system involvement (4/6 patients). All patients received intensive chemotherapy, except one patient with an EBV-associated LPD who only received rituximab. Three patients obtained a complete remission (CR), two patients had a stable disease (SD) and the last one progressed on therapy. Four patients, of whom two were in CR and one in SD, received an allogeneic HSCT during the year following the diagnosis of LPD. Two patients received peripheral blood-derived stem cells and the two other patients received bone marrow-derived stem cells. There were three matched unrelated donor (MUD) and one haplotype-mismatched family donor, with no ex vivo graft manipulation. Three of these four patients were long-term survivors after LPD (2.7, 7.7 and 9.8 years). The median life expectancy for the entire cohort is 19.1 years (range: 7.8-52.0). Three patients, two of which have received an HSCT, are still alive 2.4, 2.7 and 9.8 years after the cancer onset. The median overall survival among the five remaining patients after diagnosis of LPD was 0.5 years (from 0.3 to 7.7 years). Additional details on genetic, clinical characteristics and a centralized histopathology review are currently being studied and will be presented. In conclusion, the occurrence of LPD is less frequent than expected, may occur only in patients with WAS phenotype rather than XLT. As it impairs the prognosis of patients, HSCT could be a therapeutic option for these patients, even in partial remission of LPD. Disclosures No relevant conflicts of interest to declare.

Background: HCV chronic infection is associated with an increased risk of non-Hodgkin lymphoma (NHL) occurrence. HCV-associated NHL share homologies with primary Sjögren Syndrome (pSS)-associated NHL, and especially an association with chronic antigenic stimulation and with auto-antibody presence, especially rheumatoid factor (RF) and mixed cryoglobulinemia (MC). TNFAIP3 encodes the A20 protein that plays a key role in controlling NF-kB activation. We have previously demonstrated that germline or tumor genetic impairment of A20 plays a role in lymphomagenesis in the context of pSS[1]. The aim of this study was to assess the role of variants of TNFAIP3 in patients with HCV related NHL. Methods: Sixty-one cases of HCV-associated lymphoma with available germline DNA were drawn from the 116 patients included in the LymphoC study. Total exon sequencing of TNFAIP3was performed in a discovery set of 31 cases. Then 30 additional cases and 53 controls (HCV patients without NHL) were used for extension (ie genotyping of the rs2230926 and the TT>A dinucleotide). All our cases and controls were European. Case-only associations were tested with Fischer’s exact test. Differences in lymphoma histologic type and immunological status were assessed using Fisher’s exact test. Results:Among the 61 cases, histology subsets were 23 diffuse large B cell lymphomas (DLBCL), 17 marginal zone lymphomas (MZL), 6 splenic marginal zone lymphoma (SMZL), 5 mantle cell lymphomas, 8 follicular lymphomas, 1 chronic lymphoid leukemia and 1 chronic EBV-related lymphoproliferation. RF and MC were present in 30/61 (49.2%) and 25/43 (58.1%) of the patients respectively. Among the 53 controls, RF and MC were present in 31/53 (58.5%) and 28/53 (52.8%) of the patients respectively. We found the rs2230926G variant in 6/61 (9.8%) patients with NHL and in 7/53 (13.2%) patients without NHL meaning that there was no association between this SNP and HCV-associated NHL (OR=0.72 [95%CI 0.22– 2.28] p=0.77). We did not find any association between the variant and the marginal zone subtype of the lymphoma. However, we found that, among NHL patients, the rs2230926G allele was associated with the positivity of RF (6/30 (20%) in RF+ patients compared to 0/31 (0%) in RF- patients, OR=16.7 [95%CI 0.9 – 311.5], p=0.01). We did not find any association between the rs2230926 variant and the presence of MC patients probably due to the amount of missing data and the variability of the technic of detection. Last, we previously showed that the rs2230926G was functional and able to impair the control of NF-kB activation[1]. Conclusion: This study demonstrates that a germline coding mutation of TNFAIP3leading to a small functional defect of A20 function and of control of activation of NK-kB, plays a key role in lymphomagenesis in the context of chronic antigenic stimulation of RF+ B cells. It extends the scenario already demonstrated in Sjögren’s syndrome-associated lymphomas, a concept which is both novel and paradigm-shifting in the area of lymphomagenesis and autoimmunity. Interestingly, this coding mutation is associated only with HCV-associated lymphoma and presence of RF, which clearly supports different types of lymphomagenesis pathways in patients with HCV, one of them linked to the continuous stimulation of RF+ B cells by the immune complexes between HCV antigens and anti-HCV antibodies. Reference: 1. Nocturne, G., et al., Germline and somatic genetic variations of TNFAIP3 in lymphoma complicating primary Sjogren's syndrome. Blood, 2013 122(25): p. 4068-76. Disclosures No relevant conflicts of interest to declare.

Introduction HCV infection is associated with the development of B-cell non Hodgkin lymphomas (NHL), preferentially of marginal zone lymphomas (MZL) and diffuse large B-cell lymphomas (DLBCL) subtypes. Other subtypes of B-cell NHL are rare. HCV-related lymphomagenesis may constitute in some cases a model of lymphoma induced by chronic antigenic stimulation. Moreover, a direct role of an infection of B cells by HCV is also an alternative hypothesis. We performed a multicentric observational study of HCV-related B-cell NHL in France in order to study the real distribution of their histological subtypes and their correlation with in situ expression of HCV virus. Patients & Methods Adult patients with B-NHL and active HCV infection were included in an observational multicentric study with the exclusion of those who were co-infected with HIV. Data were collected from patients with either ongoing or past history of HCV infection. Cytological and histological samples were collected for centralized review and molecular analyses. A large panel of antibodies was performed on each sample for subtyping the B-cell NHL and HCV-NS3 antibody immunostaining was made each time we had enough material. Results Between 2006 and 2012, 133 consecutive patients were enrolled in 26 French hospitals, among them 17 patients were excluded from analysis. At lymphoma diagnosis the median age was 61 years and the gender M/F ratio was 1. Histological samples of 81/116 patients were reviewed by a panel of expert hematopathologists. The most frequent B-cell NHL subtype was DLBCL in 30/81 patients (37.5%) among them 14/30 (46.6%) were transformed from underlying low grade B-cell NHL. For 26/30 DLBCL we had enough material for performing Hans score: 18 (69%) were of non germinal center (GC) origin and 8 (31%) of GC origin. Interestingly, most de novo DLBCL were of non GC subtype (92%) whereas in transformed DLBCL 50% were of non GC subtype. MZL represent 22/81 cases (27%), 8/81 (9.9%) were follicular lymphomas and other small B-NHL subtypes represent the other cases. Patients with DLBCL displayed frequent extra-nodal involvement (digestive tract, liver) (60%) and those with MZL had the highest proportion (73%) of extranodal localisations (spleen, bone marrow, blood, eye) whereas follicular lymphomas were mainly developed in lymph nodes. Twenty-nine cases could be tested for HCV NS3 antibody, 26 exhibited evaluable staining: 12 B-NHL had in situ positive staining (most of them were DLBCL (67%) with a slight predominance of transformed DLBCL compared to de novo (62%) and 14 had negative staining (most of them were MZL or other small B-cell NHL (92%). Conclusion This study underlines the heterogeneity of HCV-related B-cell NHL with a majority of extra-nodal localizations of these lymphomas, a predominance of DLBCL and MZL and a high proportion of DLBCL developed on low grade B-NHL comparing to de novo DLBCL. We found a different GC/non GC repartition between de novo versus transformed DLBCL with a higher proportion of GC versus non GC in transformed DLBCL than in de novo DLBCL. In situ HCV virus expression was more frequently observed in DLBCL than in other subtypes of B-NHL which could indicate that the growth and development of lymphoma cells may be associated with the presence of HCV infection of B cells. Therefore, we postulate that the B cell transformation is linked with chronic antigenic stimulation in MZL and to direct infection in DLBCL. It might also explain that virological success seems to improve prognosis preferentially in MZL subtype in our series. Disclosures: Haioun: Roche: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Abstract 541 Introduction Diffuse large B-cell lymphomas (DLBCL) represent a heterogeneous group of tumors with variable clinical, morphological, and molecular features. The International Prognostic index (IPI) imperfectly stratifies patients and does not reflect the molecular heterogeneity of the disease. New tools for stratifying DLBCL patients in routine practice are needed. The aim of the study was to analyse the prognostic relevance of CMYC, BCL2 and BCL6 rearrangements and the correlation with CMYC protein expression in a large series of 776 CD20+ de novo DLBCL treated with R-chemotherapy included in the Groupe d'Etude des Lymphomes de l'Adulte (GELA) trials. Methods Patients with de novo CD20+ DLBCL were enrolled in the randomized LNH-03 GELA trials (LNH-03-1B, -2B, -3B, 39B, -6B, 7B-, 5B). Seven hundred seventy six patients treated with anthracyclin based chemotherapy (R-CHOP/R-miniCHOP=483 or R-ACVBP=293) were eligible for the study. Tumor samples were analyzed by Fluorescence in situ hybridization (FISH) using split signal FISH DNA probes for BCL2/18q21, BCL6/8q27 and CMYC/8q24 and were immunostained for the expression of CMYC protein on tissue microarrays. Results Five hundred seventy six DLBCL samples were evaluable for MYC rearrangement. Rearrangement of MYC, BCL2, and BCL6 genes were observed in 9.2% (53/576), 15.9 % (82/515), and 23.8% (129/541) of DLBCL, respectively. Fifteen cases showed both BCL2/BCL6 gene rearrangement. MYC rearranged cases (MYC-R+) included 21 MYC simple-hit (MYC-SH) and 32 MYC double or triple hit with concurrent BCL2 and/or BCL6 rearrangement (MYC-DH) DLBCL. There were 33 male and 20 women, with a median age of 62 years [range, 18–93], and 5 were stage I-II and 48 stage III-IV according to Ann Arbor. The common histological feature of the MYC-SH cases was an increased mitotic rate but a starry sky pattern with tingible body macrophages was observed only in 2 cases. MYC protein expression was found positive in 30/45 (66%) evaluable MYC-R+ cases using a cut off of ≥70% of positive tumor cells. In univariate analysis, IPI had a significant impact on OS (P< .0001). BCL2, BCL6 gene alterations did not significantly predict survival (PFS, EFS, OS). MYC-R+ breakpoint was associated with a shorter 5-year OS rate (57.7% vs 73.7%, P= 0.01) which remained significant in the R-CHOP treated group of patients (P=0.04). When separating MYC-SH and MYC-DH DLBCL, MYC-SH maintained a significant impact on survival in the global population as well as in the R-CHOP group of patients. By contrast, MYC-DH had no significant impact on OS in the global population and in the R-CHOP group of patients. In multivariate analysis, the prognostic impact of the IPI, MYC-R+ and MYC-SH breakpoint remained significant. Conclusion This is the first large extensive study on the prognosis impact of MYC rearrangement in controlled trial of DLBCL patients treated with R-chemotherapy. MYC-SH had an adverse prognostic effect on survival. Interestingly, in contrast to previous published studies, this impact was not maintained in the MYC-DH DLBCL suggesting different biological response to treatment between the two groups. Immunostaining for MYC protein was not efficient to detect MYC rearranged cases. FISH for MYC, BCL2 and BCL6 should be performed systematically to differentiate MYC-SH and MYC-DH in future clinical trials. Disclosures: No relevant conflicts of interest to declare.

1601 Background: The prognosis of follicular lymphoma (FL) remains a challenge despite stratification on the FLIPI scoring, histological grading, and microenvironement cell type infiltration. Thus, new biomarkers are needed to identify patients (pts) who require a more aggressive therapeutic strategy or targeted therapies. Transferrin receptor (TfR) is highly expressed in proliferating cells including non Hodgkin lymphoma cells. High TfR level has been associated with disease progression in chronic lymphocytic leukaemia and is observed at relapse in mantle cell lymphoma. Murine anti human TfR (CD71) antibody has been validated for histological and flow cytometric evaluation of TfR expression. The aim of this work was to assess expression and prognosis value of TfR expression on FL cells. Material and Methods: We retrospectively analyzed the expression level of CD71 in neoplastic B cells of FL lymph node biopsies at diagnosis of 45 pts who received first-line treatment with Rituximab and anthracyclines based chemotherapy at the hematology department of Necker Hospital, Paris, France, and assessed its prognosis value (second treatment free survival (TFS) and overall survival (OS)). High CD71 and Ki67 expression in FL lymph nodes biopsies were defined as upper than 25% of FL cells. CD71 expression was compared with FLIPI at diagnosis and the expression and prognosis value of Ki67 expression. Results: Characteristics of the cohort are shown in [table 1][1]. FLIPI risk was low in 7 pts (16%), intermediate in 19 (43%) and high in 18 (41%). FLIPI stratification did not show correlation with both OS and TFS in this small cohort of pts. Among 44 evaluable pts, CD71 expression was heterogeneous ranging from 0% to 90% of FL cells. T cell labeling was used as a quality control. CD71 low expression (225% of tumor cells) was observed in 31 samples (69%) and KI67 low expression in 27 (60%). After a median follow-up of 40 months (range 1 – 94) for the all cohort, TFS was 68.9 % (95 % CI 0.55–0.82) and OS was 91.1% (95% CI 0.83 – 0.99). The mean TFS after R-chemotherapy was 86 months in the low CD71 level group vs. 18 months in the high CD71 level group (p=0,075). The mean estimated OS after first R-chemotherapy was 89 months in the low CD71 group vs. 54 months in the high CD71 group (p=0,006) ([figure 1][2]). By univariate analysis, high Ki67 expression was associated with significant lower OS (p=0.035) but not TFS (p=0,162). In multivariate analysis including CD71 level, FLIPI risk, FLIPI parameter groups, CD71 was the only factor independently associated with OS (p=0,019) and TFS (p=0,037). Furthermore, Cox regression analysis did not reveal any significant correlation between Ki67 and TFS or survival. Conclusion: CD71 expression is an important independent histological prognostic factor in this monocentric retrospective study predicting OS in FL patients after first-line treatment with R anthracyclin based regimen. Ki 67 was also associated with OS in univariate analysis, but CD71 was the only independent factor associated with OS and TFS in multivariate analysis. These promising results warrant further studies in a larger prospective cohort and provide a rationale to target Tfr in relapsing refractory FL. ![Figure 1:][3] Figure 1: Overall survival (OS) after first line R anthracycline therapy according to the CD71 high and low risk groups | Characteristics | CD71 low | CD71 high | p. | |:--------------------------------------:| ---------------- | ------------- | ----- | | n (%) | 31 (69%) | 14 (31%) | | | At Diagnosis | | Age | | | | | < 60 ans | 19 | 3 | 0,045 | | 3 60 ans | 12 | 10 | | | Sex | | | | | Male | 16 | 7 | 1 | | Female | 15 | 7 | | | Clinical stage | | | | | I-II | 4 | 1 | 1 | | III-IV | 27 | 13 | | | BM involvement | | | | | Yes | 22 | 7 | 0,173 | | No | 9 | 7 | | | No. of involved nodes area (FLIPI) | | | | | 24 | 15 | 4 | 0,335 | | >4 | 16 | 9 | | | LDH | | | | | N | 22 | 12 | 0,313 | | > N | 9 | 2 | | | Hemoglobin | | | | | 3 12 g/dl | 1 | 2 | 0,204 | | < 12 g/dl | | | | | FLIPI risk group | | | | | Low | 6 | 1 | 0,251 | | Intermediate | 15 | 4 | | | High | 10 | 8 | | | Ki67 expression | | | | | Low (225%) | 23 | 8 | 0,007 | | High (>25%) | 4 | 10 | | | After treatment | | Median FU (months) | 47.8 [10.5-92.5] | 30 [1.1-75.1] | | | Need second line of treatment: No. (%) | 10 (32) | 7 (50) | ns | | Deceased: No. (%) | 1 (3) | 4 (29) | 0.03 | Table 1. Characteristics of the pts at baseline and evolution after first line R-CHOP like regimen according to the CD71 risk groups Disclosures: No relevant conflicts of interest to declare. [1]: #T1 [2]: #F1 [3]: pending:yes

Abstract 1607 Background: Lymphoid malignancies derived from T and NK cells (PTCLs) constitute a heterogeneous group of uncommon disease entities, with marked geographic variation in their distribution. The most recent data from the International T-cell Lymphoma Project based on a retrospective analysis of PTCLs diagnosed between 1990 and 2002 (Blood. 2011;117(25): 6756–67) indicate that PTCL, not otherwise specified (PTCL,NOS) represents the most common PTCL worldwide (25,9%), followed by angioimmunoblastic T-cell lymphoma (AITL) (18,5%). Over the last few years, a better characterization of the cellular origin and pathophysiology of PTCLs has led to the development of new diagnostic markers. Aim of the study: To characterize the epidemiology of mature T/NK-cell malignancies in Western Europe (France and bordering countries) and to examine whether the availability of new tools/antibodies and changing concepts over the past years might have translated into an apparent change in the relative distribution of PTCL entities. Materials and methods: The histopathological diagnosis of PTCL entities according to the 2008 WHO classification were collected through two independent sets of PTCLs in France and bordering countries. Results: Over the past two years (2010–2011), 933 newly diagnosed non-cutaneous PTCLs were reviewed in reference centers through the prospective network “Lymphopath” aiming to review any newly diagnosed lymphoma in France. According to the 2008 WHO classification, the 933 PTCLs comprised: 314 AITL (33,6%), 239 PTCL,NOS (25,6%), 78 ALK-positive anaplastic large cell lymphoma (ALCL) (8,3%), 72 ALK-negative ALCL (7,7%), 59 extranodal NK/T-cell lymphomas (ENKTL 6%), 33 enteropathy-associated T-cell lymphoma (4%), 32 HTLV1+ adult T leukemia/lymphoma (3%), 7 hepatosplenic T-cell lymphoma (1%) and 99 cases of other entities or unclassifiable (11%). A high prevalence of AITL was also found in an independent set of PTCLs retrospectively collected in the framework of a multicentric T-cell lymphoma research consortium “Tenomic” where non-cutaneous PTCL with frozen material available (n=623) from 1999 to 2009 in France and Belgium were retrieved and collegially reviewed for consensus diagnosis. In this collection, AITL (n=288, 46%) also outnumbered PTCL, NOS (n=215, 35%). Of the 196 AITL cases extensively investigated for CD10, TFH markers (PD1, CXCL13), CD21/CD23 follicular dendritic cells (FDC) and EBV, the initial diagnosis was recorded in 178 cases as: AITL in 155 cases (87%), PTCL, NOS in 21 cases (12%), and intermediate between PTCL,NOS and AITL (PTCL,NOS/AITL) in 2 cases, indicating the impact of additional stainings for the diagnosis of AITL. The 107 PTCL,NOS cases also extensively immunostained included 9 follicular variant of PTCL,NOS, 8 PTCL,NOS/AITL cases, 5 cases intermediate between PTCL,NOS and ALK-negative ALCL (of which 2 had been diagnosed as such and two as PTCL,NOS), and 85 remaining cases truly unspecified. Of these, 60 had been initially diagnosed as PTCL,NOS; 2 as PTCL,NOS/AITL; 4 as ALK-negative ALCLs and 1 as ENKTL. Conclusion: This study based on two independent large cohorts of non-cutaneous PTCLs highlights AITL as the most prevalent entity in Western Europe. It shows that extensive studies including investigation for CD10, TFH markers, FDC and EBV can at least partly contribute to the reclassification of some PTCL, NOS into the AITL spectrum category. Disclosures: No relevant conflicts of interest to declare.

Abstract 5092 Background The fact that monogenic interleukin (IL)-10 and IL-10 receptor deficiencies cause very early-onset, severe inflammatory bowel disease demonstrates the IL-10 pathway's crucial role in preventing microbiota-driven gut inflammation. However, no other severe complications of IL-10/IL-10R deficiencies have been reported to date. Methods A cohort of six patients with IL-10/IL-10R deficiency was retrospectively surveyed for phenotypic expression. The identification of a number of cases of lymphoma prompted an in-depth characterization of available biopsy material, with immunohistochemical staining, cytogenetic studies and gene expression profiling. Results Four patients (all with a complete IL-10R2 deficiency) had developed B cell non-Hodgkin's lymphoma between the ages of 5 and 6 years. Cytogenetic and IgH clonality analyses suggested that one of the patients developed at least 3 distinct lymphomas. The patients' tumors had the characteristics of diffuse large B cell lymphomas and contained monoclonal, Epstein-Barr-virus-negative germinal center B cells. Nuclear expression of the NF-κB factor c-REL was detected in all of the six lymphomas tested. Conclusions IL-10R deficiency is associated with a high risk of developing a B cell lymphoma with an unusual phenotype. Our results highlight an unexpected role of the IL-10R pathway in the control of lymphomagenesis. Disclosures: No relevant conflicts of interest to declare.

Abstract 1539 Introduction Diffuse large B-cell lymphomas (DLBCL) represent a heterogeneous disease with variable clinical outcome. Identifying phenotypic biomarkers of tumor cells on paraffin sections that predict different clinical outcome remain an important goal that may also help to better understand the biology of this lymphoma. Differentiating non-germinal centre B-cell-like (non-GCB) from Germinal Centre B-cell-like (GCB) DLBCL according to Hans algorithm has been considered as an important immunohistochemical biomarker with prognostic value among patients treated with R-CHOP although not reproducibly found by all groups. Gene expression studies have also shown that IgM expression might be used as a surrogate for the GCB and ABC subtypes with a strong preferential expression of IgM in ABC DLBCL subtype. ImmunoFISH index based on the differential expression of MUM-1, FOXP1 by immunohistochemistry and on the BCL6 rearrangement by FISH has been previously reported (C Copie-Bergman, J Clin Oncol. 2009;27:5573-9) as prognostic in an homogeneous series of DLBCL treated with R-CHOP. In addition, oncogenic MYC protein overexpression by immunohistochemistry may represent an easy tool to identify the consequences of MYC deregulation in DLBCL. Our aim was to analyse by immunohistochemistry the prognostic relevance of MYC, IgM, GCB/nonGCB subtype and ImmunoFISH index in a large series of de novo DLBCL treated with Rituximab (R)-chemotherapy (anthracyclin based) included in the 2003 program of the Groupe d'Etude des Lymphomes de l'Adulte (GELA) trials. Methods The 2003 program included patients with de novo CD20+ DLBCL enrolled in 6 different LNH-03 GELA trials (LNH-03-1B, −B, −3B, 39B, −6B, 7B) stratifying patients according to age and age-adjusted IPI. Tumor samples were analyzed by immunohistochemistry using CD10, BCL6, MUM1, FOXP1 (according to Barrans threshold), MYC, IgM antibodies on tissue microarrays and by FISH using BCL6 split signal DNA probes. Considering evaluable Hans score, 670 patients were included in the study with 237 (35.4%) receiving intensive R-ACVBP regimen and 433 (64.6%) R-CHOP/R-mini-CHOP. Results 304 (45.4%) DLBCL were classified as GCB and 366 (54.6%) as non-GCB according to Hans algorithm. 337/567 cases (59.4%) were positive for the ImmunoFISH index (i.e. two out of the three markers positive: MUM1 protein positive, FOXP1 protein Variable or Strong, BCL6 rearrangement). Immunofish index was preferentially positive in the non-GCB subtype (81.3%) compared to the GCB subtype (31.2%), (p0.4) for both cut-offs. Progression-free Survival (PFS) was significantly worse among patients with high IPI score (p Overall Survival (OS) was also significantly worse among patients with high IPI score (p All significant parameters were included in a multivariate analysis using Cox Model and in addition to IPI, only the GCB/non-GCB subtype according to Hans algorithm predicted significantly a worse PFS among non-GCB subgroup (HR 1.9 [1.3—2.8] p=0.002) as well as a worse OS (HR 2.0 [1.3–3.2], p=0.003). This strong prognostic value of non-GCB subtyping was confirmed considering only patients treated with R- CHOP for PFS (HR 2.1 [1.4–3.3], p=0.001) and for OS (HR 2.3 [1.3–3.8], p=0.002). Conclusion Our study on a large series of patients included in trials confirmed the relevance of immunohistochemistry as a useful tool to identify significant prognostic biomarkers for clinical use. We show here that IgM and MYC might be useful prognostic biomarkers. In addition, we confirmed in this series the prognostic value of the ImmunoFISH index. Above all, we fully validated the strong and independent prognostic value of the Hans algorithm, daily used by the pathologists to subtype DLBCL. Disclosures: No relevant conflicts of interest to declare.

Abstract 1754 Background: Mastocytosis is characterized by the abnormal accumulation of mast cells in various tissues responsible for organ failure and/or systemic symptoms that can be disabling and alter the quality of life (QOL). Beside symptomatic treatments, cytoreductive drugs such as a-interferon, purine analogs and to a less extent imatinib mesylate (in case of c-kit mutation other than D816V) and masatinib were shown to be effective but rare complete or long-term remissions were obtained. Thalidomide is an anti-angiogenic immuno-modulatory and anti-inflammatory drug that has preliminary been shown to have an activity in aggressive systemic mastocytosis (ASM) (Damaj et al, BJH 2008). We report the result of a multicentric, open-label, phase II study using thalidomide as a single agent in advanced SM (NCT00769587). Patients and Methods: Twenty patients (pts) were enrolled (1 missing data): smoldering systemic (SSM, n=9), ASM (n=6) and with an associated clonal hematologic non mast cell lineage disease (SM-AHNMD, n=4). Infiltrated organs were bone marrow (n=16), skin (n=14), splenomegaly (n=10), hepatomegaly (n=6), intestinal tract (n=6), lymph nodes (n=1). Median serum tryptase level at inclusion was 83.4 ng/L (range 5.3–775) and all patients except one carried the c-kit D816V mutation. Patients presented with anemia (n=6), thrombocytopenia (n=6) and neutropenia (n=1). Four patients were excluded, 1 for missing data and 3 were not evaluable. Thalidomide was administered orally at a starting dose of 50 mg/day and was progressively increased up to 200 mg/day or appearance of side effects. The duration of treatment was 6 months (1 cycle= 1 month). Responder patients may continue on thalidomide for a maximum of 12 months or progression. Primary objective was to determine the effective response rate by assessing the tumor burden. Secondary objectives were to assess the tolerance of thalidomide and to evaluate the QOL, depression (Hamilton score), pruritis, and handicap (Afirmm V2 score) related to mast cell disease. Results: Sixteen pts [7 males, 9 females; median age 65 years (range 43–76)] who received at least one cycle of thalidomide were analyzed. The median number of thalidomide cycles was 6 (range 1–20) and the median dose received was 100mg/d. Partial response was obtained in 9 pts (56%), 4 pts remained stable (25%) and 3 pts progressed (19%). Pruritis score decreased significantly from 6.5 (95% CI 4.74–12.26) to 4 (95% CI 0–5.25) (p=0.03); the Afirmm score tended to improve from 116.5 (95% CI 55.0–168.3) to 92.5 (95% CI 37.4–131.2) (p=0.38) with no improvement of QoL and Hamilton scores, median tryptase level or cytopenia. Skin infiltration disappeared only in 2 of 14 patients concerned. Treatment discontinuation was due to failure in 4 pts, side effect in 2 pts and patient's decision in 2. Thalidomide was continued in five pts as a maintenance therapy for a median duration of 6 mo (4–14). The most relevant toxicities (grade 3–4) consisted in peripheral neuropathy (12.5%) and myelosuppression (18.7%). Conclusions: Thalidomide is an acceptable and effective treatment in advanced SM. Disclosures: No relevant conflicts of interest to declare.

Abstract 109 Two previous studies conducted in the prerituximab era have demonstrated the superiority of the intensive chemotherapy regimen ACVBP over standard CHOP in DLBCL (Tilly H et al. Blood 2003;102:4284; Reyes F et al. N Eng J Med 2005;352:1197). In order to investigate the role of intensive chemotherapy associated with rituximab, the GELA initiated in 2003 a multicenter, phase III open-label, randomized trial comparing efficacy and safety of R-ACVBP vs R-CHOP in younger DLBCL patients with an age-adjusted IPI (aaIPI) of 1. Patients and methods: Patients between 18 and 59y with DLBCL and aaIPI=1 were eligible. R-ACVBP consisted of 4 induction courses given every 2 weeks: rituximab (375 mg/m2) on d1, doxorubicin (75 mg/m2) on d1, cyclophosphamide (1200 mg/m2) on d1, vindesine (2mg/m2) on d1 and 5, bleomycin (10 mg) on d 1 and 5, prednisone (60 mg/m2) from d1 to d5, and intrathecal methotrexate (IT) (15 mg) on d2, G-CSF from d6 to d13. Patients then received a sequential consolidation therapy: 2 courses of methotrexate (3 g/m2) plus leucovorin rescue, 4 courses of rituximab (375 mg/m2), etoposide (300 mg/m2) and ifosfamide (1500 mg/m2) on d1, and 2 courses of cytosine-arabinoside (100 mg/m2, SC) for 4 days, each consolidation course being administered at a 14-day interval. Standard R-CHOP was delivered every 3 weeks for 8 cycles along with IT methotrexate at d1 of the first 4 cycles. The primary objective was to evaluate the efficacy of R-ACVBP compared to R-CHOP as measured by the event-free survival (EFS). Secondary endpoints were response rate, progression free survival (PFS), disease-free survival (DFS) for complete responders, overall survival, neuro-meningeal relapse rate and toxicities. Results are presented on an intend-to-treat basis. Response to treatment was evaluated according to 1999 Cheson criteria. Results: From December 2003 to December 2008, 380 patients were randomized in 73 hematology/oncology departments of the GELA. One patient withdrew his consent the day of randomization and 379 received at least one day of study treatment, 196 with R-ACVBP and 183 with R-CHOP. Median age was 47y (18-59). Patient characteristics were well-balanced in terms of demography and baseline disease status: male gender, 59%; stage III-IV, 55%; elevated LDH, 44%; mass>10 cm, 22%; B symptoms, 28%; number of extra-nodal sites >1, 26%; bone marrow involvement, 13%. Overall response rate was 90.3% in the R-ACVBP group and 88.5% in the R-CHOP group (p=0.57). Complete remission rate (CR+CRu), was 82.7% for R-ACVBP and 80.3% for R-CHOP (p=0.56). At the time of this final analysis, in June 2010, the median follow-up was 44 months. The 3-year EFS was 80.9% (95% confidence interval (CI) 74.5–85.9) in the R-ACVBP group and 66.7% (CI 59.2–73.2) in the R-CHOP group (p=0.0035, hazard ratio (HR) 0.559). Significant differences were also observed for PFS (86.8% at 3 years (CI 80.9–91.0) vs 73.4% (CI 66.1–79.3), p=0.0015, HR 0.482), DFS (91.3% at 3 years (CI 85.1–95.0) vs 80.3% (CI 72.8–85.9), p=0.0019, HR 0.393) and overall survival (92.2% at 3 years (CI 87.1–95.3) vs 83.8% (CI 77.2–88.6), p=0.0071, HR 0.439). Patients in the R-ACVBP group experienced more frequently a serious adverse event (42% vs 15% in the R-CHOP group). Grade 3–4 hematological toxicity was more frequent in the R-ACVBP group, with a higher proportion of patients receiving red cell (51% vs 7% for R-CHOP) or platelet transfusions (13% vs 1%) and/or experiencing febrile neutropenia (39% vs 9%). There were 3 deaths (1.5%) attributed to toxicity of study treatment in the R-ACVBP group and 2 (1.1%) in the R-CHOP group. Conclusions: Compared to standard R-CHOP, intensified immunochemotherapy with R-ACVBP significantly improves EFS, PFS, DFS and overall survival with increased but manageable hematological toxicity in younger patients with DLBCL. Disclosures: Coiffier: Roche: Honoraria, Research Funding; Genentech: Research Funding. Gisselbrecht:Roche: Research Funding. Bosly:Roche: Membership on an entity's Board of Directors or advisory committees. Tilly:Amgen: Honoraria.

Abstract 4156 Introduction: Human Immunodeficiency Virus (HIV) and hepatitis C virus (HCV) infections are both associated with an increased risk of B-cell non-Hodgkin lymphoma (B-NHL). They are known to be preferentially diffuse large B-cell lymphoma (DLBCL), and Burkitt lymphoma subtypes in HIV infection, while marginal zone lymphoma (MZL) and DLBCL represent the main subtypes in HCV infected patients. The absence of increased risk of B-NHL in HIV-HCV co-infected patients compared to HIV infected patients was reported in epidemiological studies, but the clinico-pathological characteristics of B-NHL in the setting of such co-infection particularly in the era of HAART remains unclear. Patients and methods: We present the data of adult patients with B-NHL and HIV-HCV co-infection from the French ANRS CO16 Lymphovir cohort. This multicentric prospective cohort includes HIV infected patients with lymphoma. Each patient is followed every 6 months during 5 years. At each follow-up, a blood sample is withdrawn allowing ancillary studies. Data collection concerns clinical presentation, treatment and evolution of B-NHL and HIV and HCV infections. Pathological and cytological materials are centralized in order to allow their review and a concerted analysis by a group of expert hematopathologists (MR, SP, DC), haematologists and immunologists. Results: Among the 49 patients with B-NHL included in the cohort, 6 were HIV-HCV coinfected, [5 men and 1 woman, median age 47 years (range 36–67)]. They were included between october 2007 and august 2009 in 6 French centres. Transmission risk was intravenous drug abuse (n=4) and heterosexual transmission (n=2). Median duration from HIV diagnosis to B-NHL was 11 years (range 1–20), and the median nadir CD4 T-cell count was 194/mm3 (range 151–746) (nadir not available for 2 patients). Only one patient had developed AIDS before the diagnosis of NHL. HCV genotypic distribution was: genotype 1 (n=3), 2 (n=1), 4 (n=1), and not available (n=1). Median HCV viral load was 6.0 log (range 5.4–7.1). One patient had compensated cirrhosis and none of the patients were tested for cryoglobulinemia. Immunological assays showed the presence of monoclonal IgM Kappa in 1 patient and no positive rheumatoid factor. At the diagnosis of B-NHL, 4 patients received HAART and had an undetectable HIV load. In contrast, none of the patients were treated for HCV infection. The median interval between B-NHL diagnosis and last follow-up is 17 months (range 0.1–32 months). The histological subtype distribution is 4 MZL -including 2 extranodal MZL of MALT, 1 splenic lymphoma with villous lymphocytes (SLVL) and 1 lymphoplasmacytic lymphoma- and 2 EBV-negative DLBCL. All patients have extranodal involvement, including digestive tract (n=3), liver (n=2), bone marrow (n=2) and spleen (n=1). Median CD4 T-cell count at B-NHL diagnosis was 582/mm3 (range 235–1322) in MZL patients and 274/mm3 (200 and 347) in DLBCL patients. Following diagnosis, all patients were treated with HAART, associated with peg-interferon plus ribavirin in 1 patient. The 2 patients with DLBCL received R-CHOP, associated with methotrexate in 1 case. One patient with a partial response exhibited a neuromeningeal relapse and was treated with COPADM and CYVE regimen, allowing a complete and sustained response. The other patient died of serious infection after 2 courses of chemotherapy. Among patients with MZL, one patient received R-CVP and one received chlorambucil, allowing a complete response in both patients. The patient with SLVL received HAART then peg-interferon plus ribavirin, allowing normalization of lymphocytes count (5.89 at baseline vs. 1.69 × 109/L at 12 weeks of anti-HCV therapy) with a correlation between HCV virological and hematological response. Patient with lymphoplasmacytic lymphoma died of cardiac ischemia before the initiation of chemotherapy. Conclusions: This study describes the resurgence of MZL in HIV-HCV co-infected patients with restored immunity under HAART. Such B-NHL, very rarely described in HIV patients, occurs mainly in patients with control of HIV without history of AIDS but with active HCV infection. Histological subtypes and localizations resemble more to that observed in HCV infected patients than in HIV infected patients. These findings suggest the role of chronic antigenic stimulation by HCV and/or HIV and question about the interest of HCV antiviral therapy on NHL in co-infected patients. Disclosures: No relevant conflicts of interest to declare.

Abstract 3116 Background: Hepatitis C virus (HCV) associated B-cell non-Hodgkin's lymphoma (B-NHL) is a rare entity that constitutes a model of chronic immune stimulation related lymphomas. They are preferentially Marginal Zone Lymphomas (MZL) and Diffuse Large B Cell Lymphoma (DLBCL) subtypes. In order to study the characteristics of HCV-related B-NHL, we pursue a prospective multicentric observational study in France. We present here the characteristics and evolution of the patients included in this study. Patients and methods: Adult patients with a history of HCV associated B-NHL were included in the study. HCV infection was defined by a positive viral load at diagnosis of NHL. Patients with HIV infection were excluded from the study. Each patient was followed every 6 months during 5 years. Data collection included clinical presentation, treatment and evolution of NHL and HCV infection. Pathological and cytological materials were centralized and reviewed by a group of expert hematopathologists, haematologists and immunologists. Results: The data of the 64 consecutive patients included between nov 2006 and march 2010 in 20 centers are presented. Median age is 62 years (ranging from 39 to 87 years). There is a predominance of men: sex ratio 1.37 (m37/f27). HCV genotypic distribution does not differ from expected in France: 1: 52% (30/56), 2: 25% (14), 3: 11% (6), 4: 12% (7), 7 missing data. Twenty-six cases were included at diagnosis of B-NHL, 33 during follow-up of NHL and 5 at relapse. The median interval between NHL diagnosis and last follow-up is 22 months (range 0–152). The histological subtype distribution is DLBCL 39% (22), MZL 37% (21), FL 16% (9), CLL 4% (2), mantle cell lymphoma 4% (2). Remarkably, there is a continuum between MZL and DLBCL, with 6 cases with ongoing transformation. Eight cases are not classified due to small disease infiltration or lack of material. Expert review led to reclassification in few cases from DLBCL to MZL and from FL to MZL. Among the 22 patients with DLBCL, 3 have no follow-up. The median follow-up of the remaining 19 patients is 21 months. Those patients were treated with polychemotherapy combined with rituximab (R) in all cases except one. Treatment was followed by long lasting complete remission (CR) in all cases except three: a 59 y woman relapsed after Richter syndrome following CLL, a 85 y man progressed on therapy and a 40 y woman with liver DLBCL was resistant to 3 lines of R-chemotherapy. These three patients died from disease progression. During follow-up, 9 patients were treated with antiviral treatment followed by virologic response in all cases but one. The 21 patients with MZL are 8 splenic MZL including one with transformed DLBCL, 7 nodal MZL, 3 extra-nodal, and 3 Waldenstrom macroglobulinemia; 15 out of 19 cases were associated with positive rheumatoid factor (RF) and/or cryoglobulinemia. Two patients had no follow-up. The median follow-up of the remaining 19 patients is 40 months. The efficacy of antiviral treatment alone on HCV-associated MZL was confirmed in 8 patients and had a RF. The other patients were treated with R-chemotherapy (4), R+antiviral (2), R (2), oral chemotherapy (1) or “watch and wait” (1). The patient with splenic high grade transformation was treated by splenectomy alone and is still in CR. During follow-up, one patient relapsed and is currently treated with R-chemotherapy, two patients died including one after progression to DLBCL. Among the 9 patients with FL, one had no follow-up, 6 long-lasting CR were obtained following R-chemotherapy, one following three lines of treatment. One other CR was obtained following R-antiviral therapy. Three other patients received antiviral therapy during follow-up with efficacy in one case. Among the two patients with mantle cell lymphoma, one had no follow-up, the other one is on long term CR 6 years following first line chemotherapy (R-CHOP/R-DHAP). Conclusions: This study strengthens the heterogeneity of HCV-related lymphomas and the need for systematic expert review. Overall, these patients have a favourable outcome. Cases with MZL frequently respond to antiviral treatment and one case with FL to R-antiviral. Combined therapy of R- antiviral seems a good option and should be evaluated for low grade lymphomas. Patients with DLBCL should receive R-CHOP therapy and should be referred in hepatology department for antiviral treatment after chemotherapy due to frequent virologic responses and follow up of liver functions. Disclosures: No relevant conflicts of interest to declare.

Abstract 1982 Background: Systemic mastocytosis (SM) is a myeloproliferative disabling disorder for which no consensual curative therapy is currently available. Preliminary experiences in small groups of patients using cladribine (2-CdA) were encouraging, but no long term follow-up to evaluate its efficacy and safety have been reported. Patients and Methods: We studied the efficacy and safety of 2-CdA in 44 patients with mastocytosis enrolled in a compassionate program in France. Characteristics of patients were as follows: 22 male, 22 female, mean age 54y (18-83y), mean duration of disease 13 y (6m-39y). Symptoms of the disease included pigmentosa urticaria (31), Fatigue (35), flushs (24), prurit (24), abdominal pain (21), Ascite (9), diarrhea (23), weight loss (16), Headache (14), Cough (10), splenomegaly (20), Lymph nodes (6), Bone fractures (6), pleural effusions (2), Neuropsychological symptoms (19). Blood cell count showed eosinophils >0.5g/l (10), Hb2N (1/44). Patients were classified as having cutaneous mastocytosis (CM) (n=3) indolent SM (n=19), smoldering (SSM) (n=3), aggressive SM (ASM) (n=12) or SM with an associated clonal hematologic non-MC-lineage (AHNMD) (n=6), mast cell leukemia (n=1). Mean tryptase level was 158 (2.7-1240). All failed previous symptomatic therapy and/or recombinant interferon-a(n=10) or kinase inhibitors (n=7). Treatment consisted in intravenous 2-CdA (1 to 6 cycles of 0.15 mg/kg/d administered in a 2-hour infusion or subcutaneously for 5 d, repeated at 4–12 weeks), the mean number of infusion was 4.1 (1-15) to treat severe SM-related infiltration or symptoms. Results: After a median follow up of 35m (0-96m) 28 pts were alive, 14 were dead (all with ASM/ASM-AHNMD/MCL of mastocytosis progression n=5, Solid neoplasia n=2, hematological malignancy n= 3, septic shok n=4) and 2 were lost of follow up. Safety anlalysis showed 18 acute (pneumonia n=3) but no opportunistic infections except two zoster infections, and one renal tubulopathy. Five solid neoplasia were reported and one AML. Responses were observed for most of the symptoms with improvement of pigmentosa urticaria (n=24/31), fatigue (n=17/35), flushs (14/24), prurit (9/24), abdominal pain (9/21), Ascite (1/9), diarrhea (11/23), weight loss (8/16), Headache (4/14), Cough (5/10), splenomegaly (7/20), Lymph nodes (2/6), pleural effusions (0/2), Neuropsychological symptoms (5/19). Eosinophils count was normalized in 7/10 cases, Hb Conclusion: As a single agent, cladribine is an effective and safe treatment in symptomatic and aggressive SM. Cladribine improves significantly symptoms associated with the disease and may induce regression of mast cell tumoral burden. Its tolerability and efficacy argues for the possibility to use it even in ISM and symptomatic CM. Cladribine is ineffective to improve AHNMD. Further work is warranted to define the optimal regimen with respect to dose and schedule, and the usefulness of maintenance cladribine therapy. Disclosures: Hermine: Lipomed: Research Funding. Off Label Use: Cladribine.

Abstract 1927 Poster Board I-950 Introduction: Hepatitis C virus (HCV) associated B-cell non-Hodgkin's lymphoma (B-NHL) is a rare entity that constitutes a model to study chronic immune stimulation related lymphomas. They are known to be preferentially Marginal Zone Lymphomas (MZL) and Diffuse Large B Cell Lymphoma (DLBCL) subtypes. Conflicting results are reported on the association between Follicular Lymphoma (FL) and HCV. In order to study the physiopathology of HCV-related B-NHL, we pursue a multicentric observational study in France. We present here the clinicopathological characteristics of the patients included. Patients and methods: Adult patients with a history of HCV associated B-NHL are included in the study. HCV infection is defined by a positive viral load at diagnosis of NHL. Patients with HIV infection are excluded from the study. Each patient is followed every 6 months during 5 years. At each follow-up, a blood sample is withdrawn allowing ancillary studies. Data collection concerns clinical presentation, treatment and evolution of NHL and HCV infection. Pathological and cytological materials are centralized in order to allow their review and a concerted analysis by a group of expert hematopathologists, haematologists and immunologists. Results: The data of the 54 consecutive patients included between november 2006 and april 2009 in 20 french centers are presented. Median age is 63 years (ranging from 39 to 87 years). There is a predominance of men: sex ratio (m/f) is 1.45 (32/22). Included women are older than men (p Fifteen cases were included at diagnosis of B-NHL. The 39 other cases were included during follow-up of NHL. The median interval between NHL diagnosis and last follow-up is 15 months (range 0-13y). The histological subtype distribution is DLBCL 39% (21), MZL 35% (19), FL 13% (7), CLL 6% (3). Remarkably, there is a continuum between MZL and DLBCL, 6 cases with ongoing transformation. Four cases could not be classified due to small disease infiltration or lack of material. We confirm the link between cryoglobulinemia and MZL, 12+ out of 17 tested, 6+/12 in DLBCL versus 2+/5 in FL and 1+/2 in CLL. Nodal involvement is infrequent (5 out of 21 cases of DLBCL, 2/19 MZL, 4/7 FL). Extranodal involvements predominated in spleen (15 including 8 MZL), lung (6), digestive tract (4), liver (3), heart (1), skin (6) and bone marrow (4). The efficiency of antiviral treatment is confirmed in 5 cases with MZL, and remarkably, was followed by a good response in one case with FL. However, most patients in this observational study received treatment with Rituximab (R) either alone (5 cases with MZL), or combined with chemotherapy (including 15 cases with DLBCL and 4 with FL) or with antiviral treatment. This was associated with good clinical responses in most cases and low toxicity. Indeed, only 5 patients died during follow-up – two from disease progression - a 85 y man and a 40 y woman with liver DLBCL who was resistant to 3 lines of R-chemotherapy. The other patients died of sepsis (2), and cardiac ischemia (1). Conclusions: This study strengthens the heterogeneity of HCV-related lymphomas. The observation of cases with MZL and, remarkably, of one case with FL responding to antiviral treatment suggests that they are both linked to chronic immune stimulation. Therefore, the concept of antigen-driven lymphomagenesis seems more heterogeneous than initially anticipated: it could involve a T independent response in MZL, and a T dependent response in FL. The ongoing pathophysiological study will improve further understanding of the mechanisms by which antigen-driven lymphoproliferation arise. Disclosures: No relevant conflicts of interest to declare.

Hemophagocytic syndrome (HPS) is characterized by an uncontrolled proliferation of macrophages displaying extensive phagocytosis of hematopoietic cells that can be associated with non Hodgkin lymphomas. However, Hodgkin lymphoma associated with hemophagocytic syndrome (HL-HPS) has rarely been published. We report here a large series of 34 patients presenting HL-HPS. Histological analysis and Epstein-Barr Virus (EBV) studies were performed. The 34 patients were enrolled from 1992 to 2006. HPS diagnosis was based on usual clinico-biological criteria. Bone marrow aspiration or biopsy were performed in all cases and confirmed HPS, showing hemophagocytic features in scattered macrophages. HL was documented on histological material in all 34 patients. The biopsies were performed on different localizations: lymph nodes (n=18), bone marrow (n=27), liver (n=2) and tonsil (n=1). All histological slides were reviewed and classified according to the World Health Organization (WHO) Lymphoma classification. The presence of EBV in the tumour cells was detected using EBER RNA in situ hybridization and the expression of viral proteins LMP-1, EBNA-2 by immunoperoxidase. Patients were 26 men and 8 women (sex ratio M/F = 3.3). The median age was 45 years (range 19–84). HIV status was negative in 26 patients and positive in 8 patients. All patients were in clinical stage IVB. HL subtypes (18 lymph nodes) were Mixed Cellularity (n=12, 67%), Nodular Sclerosis (n=2, 11%) and Lymphocyte Depleted (n=4, 22%). Extra nodal tissues were highly infiltrated by tumour cells in all cases. The presence of EBV in tumour cells was detected in 32 out of the 34 patients (94%). In all EBV positive cases, high levels of LMP-1 without EBNA2 expression were detected, defining a latency II. This study reports the largest series to date of HL-HPS. The features of HL-HPS are particular by the high proportion of mixed cellularity subtypes (67%) in contrast to the frequency of nodular sclerosis subtypes observed in the general population of non overt immunosuppressed patients, and by the striking high proportion of EBV associated HL (32 out of the 34 patients, 94%). Our findings suggest not only a pathogenic role of EBV, but also a defective immune system in the control of EBV infection in HL-HPS patients.The high predominance of male in our population of HPS-HL (sex ratio M/F = 4.3 after exclusion of HIV positive patients) and the strong association with EBV could suggest X-linked immune defect in these patients.

High amounts of intra-tumoral reactive macrophages have been reported to be associated with a poor prognosis in patients with follicular lymphoma (FL) (Blood2005;106:2169). However, this study has been retrospectively performed in a patients’ population selected before the monoclonal antibody therapeutic area, and has not been confirmed on independent series. To establish whether the intra-tumoral macrophages count (MC) is definitely able to predict the outcome of FL patients, we analysed both immunohistochemical CD68 expression and clinical outcome in patients included in the GELA-GOELAMS FL-2000 trial (ASH-2004; ASCO-2006). Patients between 18 and 75 years of age with high tumor burden FL were randomized to receive either CHVP-I or R-CHVP-I. Among the 358 patients included on the basis of histologically proven FL after reviewing by 3 hematopathologists, 194 had available biopsy specimen. Clinical characteristics of those 194 patients were not different of those of the whole population and median time to event was 43.1 months in 92 pts receiving CHVP-I arm and 54.5 months in the 102 pts receiving R-CHVP-I. Slides were stained with the anti-CD68 KP1 antibody using a standard IHC procedure, then scored on high power field (hpf) (× 400 magnification) by 3 different pathologists. Analysis of the relative risk of event according to the intra-follicular MC (IF-MC) led us to determine a single cut-off point to categorize the covariate, the best cut-off point being estimated to be 10 macrophages/hpf. The IF-MC was equal or less than 10 intra-follicular KP1+ macrophages/hpf in 53 patients, and more than 10 in 141 patients. With this cut-off of 10, a low MC was significantly associated with a better EFS for all patients (p=0.011). However, this effect was predominantly observed in patients that received CHVP-I (p=0,012, OR) but not in those receiving R-CHVP-I (p=0.15).Multivariate analysis adjusting for 10 IF-MC cut-off (p

Classical Hodgkin lymphoma (cHL) belongs to the most curable lymphomas in adults. Some cHL however, are primary refractory to usual treatments including anthracyclins regimen. Currently, only clinical factors are considered as relevant for prognosis. In a previous study of a small cohort of patients, we showed that some immunohistochemical markers could help for predicting the treatment response of cHL. In this study, we extended the markers and increased the number of included patients. We performed a retrospective study on pre-treatment biopsy specimen of 59 patients, 18 with primary refractory cHL and 41 responders to chemotherapy and free of disease for at least 3 years. Most refractory cHL had a nodular sclerosis (NS) histological type, except one which was a mixed cellularity type. Thirty six responders had a NS type, 3 patients had a mixed cellularity type and the 2 others an interfollicular cHL. The semi-quantitative immunohistochemical study used CD20, CD3, CD30, bcl2, p53, Ki67, TiA1 and c-kit antibodies. The results were statistically evaluated using a Fisher ’s exact test or a Wilcoxon sum rank test depending on the variable studied. CD30 and Ki67 stained strongly Hodgkin (Hg) and Reed-Sternberg (RS) cells regarless the response status. In contrast, these cells expressed significantly less frequently CD20 in refractory cHL than in responders (p= 0.032) and were never stained with CD3. P53 and bcl2 had a significantly higher expression on Hg or RS cells in refractory cHL (median = 63% & 51%) compared to responders (median = 40% & 12%) (p=0.004 & p=0.015 respectively). The cytotoxic marker TiA1 stained significant higher number of small lymphocytes in refractory cHL (median=42.5 per high power field (hpf)) compared to responders (median= 21 per hpf) (p= 0.0006). C-kit antibody was negative in Hg or RS cells but stained significant more mastocytes in refractory cHL (median=9 per hpf) comparing to responders (median=3.8 per hpf) (p= 0.001). These results indicate that immunohistochemical markers are useful in cHL and should be used in association with clinical parameters for predict the cHL treatment response. The prognostic significance of CD20 expression in cHL is controversial but in this study seems predictive of a better treatment response and is merely a marker of different gene expression program that may be associated with a more favorable outcome. A high bcl2 and p53 expression in refractory cHL supports the notion that an intact apoptosis cascade is essential for cell killing effect of chemotherapy. The increasing of TiA1 and c-kit positive cells raises the importance of the environmental non-neoplastic cells in cHL and suggests that targeted therapy against mast cells could improve prognosis of refractory cHL.