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Adenosine deaminase 2 deficiency (DADA2) is a recently defined inborn error of immunity caused by loss-of-function mutations in the ADA2 gene. Patients suffer from severe manifestations, including early-onset lacunar strokes, intracranial hemorrhages, vasculitis/vasculopathy, systemic inflammation, immunodeficiency, and hematologic abnormalities. The therapeutic benefit of the current treatments is unsatisfactory. Anti-tumor necrosis factor therapy reduces strokes and systemic inflammation but does not correct cytopenia and bone marrow failure. Allogeneic hematopoietic stem/progenitor cell (HSPC) transplantation can ameliorate most disease manifestations, but patients are at risk for complications. Therefore, we proposed that autologous HSPC gene therapy may be an alternative curative option for patients who has no compatible donor or cannot receive intense chemotherapy. We performed an in-depth study, using multiparametric flow cytometry, of the bone marrow (BM) cell composition of three adult patients with the hematological phenotype of DADA2. Compared with healthy donors (HDs), patients' BM exhibited a reduced number of mature and immature populations belonging to different hematopoietic lineages. Patients exhibited a substantial reduction in circulating neutrophils and hematopoietic stem cells and progenitor pools in the BM. Severe neutropenia and HSPC defects are direct causes of DADA2. Indeed, ADA2 knock-down in zebrafish - as rodents do not harbor an ADA2 orthologue gene - caused a significant decrease in neutrophil and HSPC numbers, reminiscent of patients' phenotype. Administration of human recombinant ADA2 effectively corrected both neutropenia and defective hematopoiesis in the zebrafish embryo. We used a third-generation LV to restore constitutive ADA2 expression in HSPCs. Transduction of healthy donors' HSPCs allowed efficient delivery of the functional ADA2 enzyme with no toxicity. Supranormal ADA2 expression in healthy donors' and patients' HSPCs was well-tolerated and did not impact HSPC multilineage differentiation potential in vitro and in vivo. We also assessed whether LV-derived ADA2 could correct the hyperinflammatory M1 macrophage phenotype characteristic of DADA2. ADA2 reconstitution in patients' macrophages led to the normalization of IL-6 and TNF release. Similar results were obtained using M1 macrophages differentiated from ADA2-transduced HSPCs. Altogether, our findings indicate that HSPC gene therapy is a promising approach to re-establish stable ADA2 activity and correct the hematological and inflammatory manifestations in patients with DADA2. Disclosures Aiuti: Orchard Therapeutics: Other: PI of clinical trials sponsored by company.

Background: Wiskott-Aldrich syndrome (WAS) is a rare, X-linked, life-threatening primary immunodeficiency caused by mutations in the gene encoding the WAS protein (WASP). WASP-deficient immune cells have compromised immunological synapse formation, cell migration and cytotoxicity. Thus, WAS is characterized by development of recurrent or severe infections, eczema, and increased risk of autoimmunity and malignancies. In addition, WASP deficiency results in microthrombocytopenia, leading to severe bleeding episodes. When a suitable donor is available, WAS can be treated by hematopoietic stem cell transplant (HSCT), but HSCT can be impeded by complications such as graft versus host disease, rejection and autoimmunity. Importantly, HSCT may carry higher risks in older children (>2-5 yrs) [Shin et al, 2012; Moratto et al, 2011]. An alternative approach is gene therapy (GT). We previously reported interim results of a Phase I/II clinical trial (NCT01515462) in 8 subjects treated with OTL-103, a drug product composed of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) transduced ex vivo with a lentiviral vector (LV) encoding human WASP cDNA under the control of the endogenous promoter [Ferrua et al, 2019]. We now report updated results on the safety and efficacy of OTL-103 in 17 subjects treated at San Raffaele Hospital as part of the same clinical trial or expanded access programs (EAP) with up to 8 yrs follow up (FU). Methods: NCT01515462: As described in Ferrua et al, 8 male subjects (mean age at GT: 4.8 yrs, range 1.1-12.4) were treated with OTL-103. The source of autologous CD34+ HSPCs was bone marrow (BM; n=5), mobilized peripheral blood (mPB; n=2) or both (n=1). As part of a reduced-intensity conditioning regimen, rituximab was given 22 days prior and busulfan + fludarabine during the week before OTL-103 infusion. At time of reporting, all subjects had ≥3 yrs FU (range: 3-8 yrs). EAP: 9 male subjects (11.2 yrs, 1.4-35.1) received identical treatment to subjects in the clinical trial; autologous CD34+ HSPCs source was mPB in all subjects. At time of reporting, subjects had a median of 1.4 yrs FU (range: 0.1-3.0 yrs) with 6/9 having ≥1 yr FU. Results: At last FU for all subjects (median: 3.0 yrs, range 0.1-8.0), overall survival was 94% (16/17). One EAP subject died 4.5 mo post-GT, due to deterioration of an underlying neurodegenerative condition considered unrelated to OTL-103 by investigator. To date, there have been no reports of insertional oncogenesis or replication-competent LV. While most subjects experienced adverse events (AEs) due to the reduced-intensity conditioning regimen (mainly mild or moderate), there were no reports of AEs related to OTL-103. Efficacy endpoints analyses were performed on surviving patients with ≥1 yr FU. Evidence of engraftment of genetically corrected HSPCs and LV+ colonies in BM was observed within 3 mo and persisted up to 8 yrs - the longest published FU of LV vector durability to date (Figure). WASP expression was restored after GT, shown by increases in the fraction of WASP+ lymphocytes and platelets (PLT) within 3 mo and maintained thereafter (Table). After GT, PLT counts improved, leading to a reduction of frequency and severity of bleeding events. Independence from PLT transfusions and absence of severe bleeding events were observed in all subjects by 9 mo FU (Table). Immune function improved; all evaluable patients discontinued immunoglobulin supplementation after GT (median time to discontinuation: 0.9 years after GT, range: 0.2-5 years). Furthermore, reduction in severe infection rate was observed post-GT, suggestive of immune reconstitution (Table). The decrease in bleeding events and severe infection rates occurred despite the integration of subjects into normal daily activities. Eczema progressively resolved or was reduced compared to baseline. Conclusions: This combined analysis of 17 subjects treated in a clinical trial or EAP with up to 8 yrs FU demonstrates that GT continues to be an effective treatment for WAS. All surviving subjects achieved high levels of multilineage engraftment, sustained restoration of WASP expression in lymphocytes and PLTs, improved PLT counts, and fewer bleeding events. A significant reduction in severe infection rate suggests reconstitution of immune function. Importantly, clinical benefit was also attained in older subjects (>5 yrs), a group considered at higher risk when treated with allogeneic HSCT. Disclosures Jones: Orchard Therapeutics: Employment, Equity Ownership. Dott:Orchard Therapeutics: Employment, Equity Ownership. Naldini:Genenta Science: Consultancy, Equity Ownership; Magenta Therapeutics: Equity Ownership; San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), a joint venture between Fondazione Telethon and Ospedale San Raffaele (OSR): Other: Wiskott-Aldrich Syndrome (WAS) gene therapy was licensed to GlaxoSmithKline (GSK) in 2014. It was then licensed to Orchard Therapeutics (OTL) in April 2018. OTL is the current sponsor of the clinical trial.. Aiuti:San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), a joint venture between Fondazione Telethon and Ospedale San Raffaele (OSR): Other: Wiskott-Aldrich Syndrome (WAS) gene therapy was licensed to GlaxoSmithKline (GSK) in 2014. It was than licensed to Orchard Therapeutics (OTL) in April 2018. OTL is the current sponsor of the clinical trial.; San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), a joint venture between Fondazione Telethon and Ospedale San Raffaele (OSR): Other: Study PI.

Despite the success of autologous anti-CD19 CAR T cell therapy in B-Acute lymphoblastic leukaemia (B-ALL) and Diffuse Large B Cell Lymphoma (DLBCL), treatment failures occur. One contributing factor may be the intrinsic T cell fitness of the CAR T cell product that is influenced by the underlying malignancy and prior treatments. With the advent of gene editing, 'off the shelf' non-HLA matched healthy donor (HD) CAR T cells are under investigation for the treatment of patients (pts) in clinical trials. UCART19 (S68587) is a first-in-class allogeneic CAR T cell product expressing a second generation anti-CD19 CAR with TALEN®-mediated gene knockouts of T cell receptor alpha chain (TRAC) and CD52 to prevent graft versus host disease and to render them resistant to anti-CD52 antibody used for lymphodepletion. Preliminary clinical trial data on the use of UCART19 in B-ALL was previously reported at ASH (Benjamin et al, 2018). The phenotypic and functional characteristics of CAR T cell products manufactured from B-ALL, Chronic Lymphocytic Leukaemia (CLL) and DLBCL pts were compared to young adult healthy donor (HD) CAR T cell products. In addition, potential effects related to knocking out TRAC in HD TCR-CAR T cells were examined. Thawed PBMCs from B-ALL, CLL, DLBCL pts and HDs underwent T cell enrichment, activation with anti-CD3/CD28 beads and IL-2, followed by transduction with anti-CD19 4-1BB CD3ζ lentiviral CAR construct and expansion. HD TCR- CAR T cells were manufactured by electroporation of HD CAR T cells with mRNA coding for TRAC TALEN® and residual TCRαβ+cells were removed by magnetic bead selection. CAR expression levels, T cell subsets, and exhaustion markers were examined by flow cytometry. Expression of activation markers CD25 and CD69 was measured in response to co-culture with the CD19+cell line NALM-6. Cytotoxicity against NALM-6 and Raji was assessed and antigen-mediated proliferation measured over 14 days. HD CAR T cells (n=11) expanded significantly more during manufacture than CAR T cells derived from B-ALL (n=9), CLL (n=8) or DLBCL (n=8) pts. As expected, the electroporation step resulted in a transient decrease in viability which recovered over time in culture (n=10). Median CAR expression level was higher on CLL CAR T cell products compared to those from B-ALL pts and HDs, thought to be due to a higher CD4:CD8 ratio in some CLL products. As a consequence of TCR knockout, CD3 expression was lost on HD TCR- CAR T cells (n=10), apart from a small population of γδ CAR T cells. CLL and DLBCL CD8+CAR+cells expressed higher levels of PD1 than HD CD8+CAR+cells. DLBCL CD4+CAR+cells also expressed significantly higher levels of PD1 than HD or HD TCR-CD4+CAR+T cells. CAR+CD8+CD27+PD1- T cells have been previously described as a functionally important population that correlated with clinical outcome in pts who received CLL CAR T cells (Fraietta et al, 2018). We found HD (n=13) and HD TCR- (n=10) CAR T cells had significantly more CD8+CD27+PD1- CAR T cells compared to those derived from CLL (n=8) and DLBCL (n=6) pts, but similar levels to B-ALL pts (n=10). In the absence of CD19 antigen, DLBCL CAR+CD8+ T cells (n=6) had greater expression of CD25 and CD69. However, in response to stimulation with CD19+ NALM-6 cells, HD (n=12), HD TCR- (n=10) and B-ALL (n=10) CAR T cells had higher fold increase in CD69+ cells compared to DLBCL (n=6) CAR T cells. On paired analysis (n=6), no difference was seen in activation in response to CD19 antigen on HD compared to HD TCR- CAR T cells. All CAR T cell products demonstrated comparable cytotoxicity against NALM-6 and Raji cell lines in short term in vitro assays. However, long-term cytotoxicity will be evaluated in a murine model. We performed a detailed comparison of the phenotypic and functional characteristics of CAR T cells derived from pts with B-cell malignancies and HDs. DLBCL CAR T cells showed lower antigen specific activation but higher baseline activation which could lead to more differentiated exhausted T cells. CAR T cells derived from HDs show a higher proportion of the therapeutically relevant CAR+CD8+CD27+PD1- cells compared to patients with mature B cell malignancies (CLL and DLBCL), which is maintained after TRAC knockout. This suggests allogeneic CAR T cells, such as UCART19, may provide a more effective product for pts with T cell dysfunction. Disclosures Graham: Gillead: Other: Funding to attend educational meeting; Servier: Research Funding. Jozwik:Servier: Research Funding. Metelo:Pfizer: Research Funding; Allogene: Research Funding. Almena-Carrasco:Servier: Employment. Peranzoni:Servier: Employment. Ramsay:Celgene Corporation: Research Funding; Roche Glycart AG: Research Funding. Dupouy:Servier: Employment. Farzaneh:Autolus Ltd: Equity Ownership, Research Funding. Patten:Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria; Roche: Honoraria, Research Funding. Benjamin:Amgen: Honoraria; Allogene: Research Funding; Gilead: Honoraria; Servier: Research Funding; Eusapharm: Consultancy; Pfizer: Research Funding; Takeda: Honoraria; Novartis: Honoraria.

Ataxia telangiectasia (A-T), a genetic disorder caused by the homozygous mutation of the ATM gene, frequently associates with variable degrees of cellular and humoral immunodeficiency. However, the immune defects occurring in patients with A-T are still poorly characterized. Here we show that the T-cell receptor (TCR) variable β (BV)–chain repertoire of 9 A-T patients was restricted by diffuse expansions of some variable genes prevalently occurring within the CD4 subset and clustering to certain TCRBV genes (eg, 5.1, 11, 14, and 23). In addition, the study of the third complementarity-determining region (CDR3) showed, in all patients, significantly altered profiles in most BV genes examined suggesting diffuse oligoclonal expansions. The sequencing of TCR CDR3 regions revealed completely normal V(D)J coding joints and confirmed a reduced diversity of the antigen-receptor repertoire. The B-cell repertoire was similarly restricted and skewed by diffuse oligoclonal expansions with normal V(D)J joints. Thymic output, evaluated by measuring TCR rearrangement excision circles, was extremely low. The majority of peripheral T cells had the phenotype and the function of effector memory cells, indicating that in vivo they are able to respond normally by terminal differentiation to antigenic stimulation. These results indicate that ATM mutation limits the generation of a wide repertoire of normally functioning T and B cells.

Introduction. Rituximab has been demonstrated to be effective either as intralesional or as systemic therapy in PCBCL, We report our experience in the treatment of PCBCL with intravenous Rituximab. P atients and Methods From February 1999 to February 2014 we treated 75 patients: 47 Follicle Center Lymphoma, 23 Marginal Zone Lymphoma, 5 Diffuse Large Lymphoma Leg type. The stage was T1 in 38 pts, T2 in 22 pts and T3 in 15 pts. In 24 patient prior treatment included: CHT (11), Radiotherapy (4), Surgery (4) or alpha2Interferon (IFN) (5). Rituximab at dosage of 375 mg/m2 for a minimum of 4 cycles, was administered alone (51 patients) or in association with CHT (13). RT (2) or IFN (3). Results. No patient presented adverse effects during the Rituximab infusion. A reduction of circulating B lymphocytes was observed for 11 months, on the average, without an increased risk of infections. No added toxicity was observed in patients treated with Rituximab plus CHT. Overall response rate was 97,3% (CR 82,6 %, PR 14,6 %). Five–years Overall Survival (OS) was 86,9% with Disease Free Survival of 57%. According to stage OS was in T1 94,3%, in T2 90,5%, in T3 73,6%. (T1+T2 vs T3: p Conclusions. Rituximab is effective and safe in the treatment of PCBCL even in heavily-treated or elderly patients. In our patients only the stage of disease was significant for the prognosis. A higher number of patients are necessary to indicate Rituximab in biological and clinical subsets of patients as a front-line therapy. Disclosures No relevant conflicts of interest to declare.

Hematopoietic stem cells (HSC) are endowed with the unique role of generating an adequate and efficient pool of blood cells throughout human life. Data derived from clonal tracking of HSC activity and hematopoietic dynamics directly in vivo in humans would be of paramount importance for the design of therapies for hematological disorders and cancers. Our gene therapy (GT) clinical trials for adenosine deaminase (ADA) deficient-SCID and Wiskott-Aldrich Syndrome (WAS) based on the infusion of genetically engineered HSC, constitute unique clinical settings where each vector-marked progenitors and its blood cell progeny is traceable being univocally barcoded by a vector integration site (IS). To study early dynamics of hematopoietic reconstitution in humans, we collected by LAM-PCR + Illumina-Miseq sequencing 14.807.407 sequence reads corresponding to 71.981 IS tagging clones belonging to 13 different cell types purified from the bone marrow and the peripheral blood of 4 WAS patients up to 36 months after GT. We firstly identified and quantified identical IS shared among CD34+ progenitors, and mature Myeloid/Lymphoid cells as marker of the real-time clonal output of individual vector-marked HSC clones in vivo. We unraveled the timing of short, intermediate and long term HSC output showing that CD34+ clones active at 3-6 months after GT are not detectable at later follow up. By unsupervised clustering of IS similarities among lineages we unveiled diverse input of HSPC clonal differentiation towards lymphoid, myeloid and megakaryo-erythroid cells and found that NK cells have a distinct relationship with HSPC as compared to T and B cells. We also profiled the level of HSPC output overtime showing that early reconstitution is markedly skewed towards myeloid production. Importantly, clonogenic progenitors generated in vitro from ex vivo purified CD34+ patients’ cells, showed a IS profile coherent with that of freshly purified BM and PB cell types from the same time-point. We also studied population clonal entropy through 7 different diversity indexes and uncovered that progenitor output occurs in distinct waves during the first 6-9 months after transplantation reaching a “homeostatic equilibrium” only by 12 months after GT. At steady state we estimated by mark-recapture mathematical approaches that 1900-7000 transduced HSC clones were stably contributing to the progenitors repertoire for up to 3 years after infusion of gene corrected CD34+ cells. To evaluate the long-term preservation of activity by transplanted HSC we exploited data derived from the IS-based tracking of 4.845 clones in ADA-SCID patients performed for up to 6 years after GT. We showed that identical IS are consistently detected at multiple lineages level even several years after GT. Strikingly, by semi-quantitative PCRs on specific vector-genome junctions we tracked a fluctuating but consistent output of marked HSC over a period of 5 years without the manifestation of clonal quiescence phases. Additionally, since the gamma-retroviral vector used in ADA-SCID HSC-GT trial is able to transduce only actively replicating cells, we provided the first evidence that in vitro activated HSC, “awaken” from dormancy, can still, once infused, retain in vivo long-term activity in humans. We exploited IS similarities among the lineages for both WAS and ADA-SCID datasets to reconstruct the hematopoietic hierarchy by combining conditional probability distributions and static/dynamic graphical models of dependencies. Notably, preliminary data unveiled a link between myeloid progenitors and mature lymphoid cells that supports the recently suggested model of hematopoiesis based on a delayed branching of myeloid and lymphoid lineages. Further mathematical models are being applied to specifically study population dynamics and single HSPC contribution to hematopoiesis including stochastic models of neutral clonal drift. More detailed analysis are also being performed on IS collected from 7 distinct CD34+ subtypes isolated from GT patients and FACS sorted according to the most recent markers of HSPC differentiation. Overall our work constitute the first molecular tracking of individual hematopoietic clones in humans providing an unprecedented detailed analysis of HSC activity and dynamics in vivo. The information gathered will be crucial for the design of therapeutic approaches for a broad spectrum of hematological diseases and tumors. Disclosures Neduva: GSK: Employment. Dow:GSK: Employment.

Evidence indicates that, at least in the early stage, Kaposi's sarcoma (KS) is a cytokine-mediated disease and that it is consistently associated with a novel herpesvirus termed human herpesvirus-8 (HHV-8). To gain insights into the mechanisms by which cytokines and HHV-8 may cooperate in disease pathogenesis, we examined the phenotype, the Th1 (gamma-interferon [gamma IFN]) and Th2 (interleukin-4 [IL-4] cytokine profile and the presence of HHV-8 in peripheral blood mononuclear cells (PBMC), tumor-infiltrating lymphocytes (TIL), and spindle cell cultures derived from skin lesions of patients affected by classical KS (C-KS) and acquired immunodeficiency syndrome (AIDS)-associated KS (AIDS-KS). TIL and spindle cell cultures were examined at day 0 or after culture in conditioned media from activated T cells (TCM) that contain the same cytokines increased in KS tissues. No differences were found in the immunophenotype of PBMC from C-KS patients versus controls, except for AIDS-KS patients who showed a T-CD8+ expansion. However, a preferential infiltration of T-CD8+ cells was found in all KS lesions examined, which was maintained after culture of TIL in TCM. gamma IFN production was found in both PBMC and cultures derived from all KS examined; some IL-4 positive supernatants were found only in three AIDS-KS cases. Uninvolved skin did not show appreciable lymphocyte infiltration or cytokine production. The culture conditions of the lesional skin allowed also the appearance of adherent, spindle-like cells bearing markers of tissue macrophages. Finally, most or all of the PBMC, lesions, and macrophagic cell cultures from the skin lesions were found to be positive for HHV-8 infection by nested polymerase chain reaction (PCR). These findings indicate that patients with KS express a Th1 phenotype with a prevalent gamma IFN production, likely accounted for by the local T-CD8+ infiltration. By analogy with other viral infections (i.e., Epstein-Barr virus), this suggests that in loco recruitment of lymphoid cells and the subsequent gamma IFN production may be in response to or elicited by HHV-8 that was found in both PBMC and macrophagic cell cultures from the lesions of the same patients.

Abstract 4814 Sezary Syndrome (SS) is characterized by specific chromosomal abnormalities, however is not completely clarified yet which are the genetics hits associated to the initial phase or associated to disease progression. In this study, employing both high density Comparative Genomic Hybridization array (aCGH) and Single Nucleotide Polymorphism (SNP) array technologies, we elucidated the most frequent and significant chromosomal gain and loss regions, and new potentially relevant aberration for the disease progression onset. A total of 30 samples derived from 18 SS patients were analyzed on the Gene Chip Human Mapping 10K Array (Affymetrix). Genotype call and signal information performed by dChip SNP Software (http://www.dchip.org) provided us normalization and simultaneous measurement of Loss of Heterozygosity (LOH) and DNA Copy Number (CN) changes. We have further refined our analysis with a systematic method, Genomic Identification of Significant Targets in Cancer (GISTIC), able to identify regions that were significantly amplified o deleted, assigning a G-score that considers the amplitude of the aberration as well as the frequency of its occurrence across samples (http://genepattern.broadinstitute.org). Our data, generating by the integration of this two methods (see Table 1), revealed 19 significant focal event, including 10 amplification (10p, 17q, 8q, 6p, 4p, 1q, 18q, 21q, 3q, 1p) and 9 deletions (14q, 17p, 10p, 9p, 8p, 13q, 12p, 6q, 2p). In addition, new significant aberrant regions were identified, such as losses of 9p21.3, locus of an important tumor-suppressor gene CDKN2A (p16INK4a/p14ARF) and CDKN2B (p15INK4b). Recently, several study have reported the great influence of alteration in p16INK4a/p14ARF for prognosis of Diffuse large B-cell lymphoma (DLBL), primary cutaneous DLBCL leg-type, Blastic plasmacytoid dendritic cell neoplasm (BPDCN). Across our set of samples, 9p21.3 deletion occur in 8/30 samples from 6 patient, prevalently in heterozygosity state (Log2 ratio from −0.3484 to –0.7691). Two cases presented homozygous deletion (Log2 ratio from −1.2157 to –1.5342), and in four patients losses appeared only in a following phase of observation, suggesting a tumor progression event. Table 1 Significant regions of chromosomal gain Genes in Region Significant regions of chromosomal loss Genes in Region Cytoband Q value GISTIC peak Cytoband Q value GISTIC peak 10p12.33 8.07E-13 17765313-19264851 8 14q11.2 1.85E-40 21395737-22130391 1 17q11.1 3.54E-09 20147238-62034035 563 17p13.1 2.15E-10 1-15053486 234 8q22.3 2.93E-07 70887466-146274826 314 10p11.22 1.98E-07 30280444-32664641 8 6p25.3 0.0020062 1-1263549 6 9p21.3 0.00074825 21283632-22089567 11 4p15.32 0.0071803 17395812-20340589 4 8p23.3 0.00076308 1-32177352 179 1q23.3 0.039674 158849705-159641626 8 13q21.31 0.0028295 63681448-65120691 0 18q22.3 0.1913 1-76117153 251 12p13.1 0.025412 9304151-17414118 85 21q22.3 0.1913 1-46944323 223 6q24.1 0.029124 139319577-141635965 4 3q29 0.2191 169050880-199505740 163 2p23.3 0.043403 24636437-43910832 126 1p36.31 0.11633 1-20338260 239 Disclosures: No relevant conflicts of interest to declare.

Abstract 3238 Poster Board III-175 We have used single nucleotide polymorphism (SNP) and comparative genomic hybridization array (aCGH) to study DNA copy number (CN) changes and loss of heterozygosity (LOH) in a series of 28 patients affected by Sézary syndrome (SS), a rare form of cutaneous-T-cell lymphoma (CTCL). Our data identified, further confirming previous studies, recurrent losses of 17p13.2-p11.2 and 10p12.1-q26.3 occurring in 71 and 68% of cases respectively; common gains were detected for 17p11.2-q25.3 (64%) and chromosome 8/8q (50%). Moreover, we identified novel genomic lesions recurring in more than 30% of tumours: loss of 9q13-q21.33 and gain of 10p15.3-10p12.2. Individual chromosomal aberrations did not show a significant correlation with prognosis, however when more than three recurrent chromosomal alterations (gain or loss) were considered, a statistical association was observed using Kaplan-Meier survival analysis. Crossing genomic data mapping with those obtained from gene expression profiles of matching samples we were able to identify a total of 113 deregulated transcripts in aberrant chromosomal regions that included cancer related genes such as members of the NF-kB pathway (NKIRAS2, PSMD3, BAG4, BTRC, TRAF2) that might explain its constitutive activation in CTCL. Matching this list of genes with those discriminating patients with different survival times we identify several common candidates that might exert critical roles in SS, like PIP5K1B and BUB3. Taken together this study confirms and maps more precisely the regions of gain and loss and, combined to transcriptional profiles, suggest a novel set of genes of potential interest in SS. Disclosures No relevant conflicts of interest to declare.

Sézary Syndrome (SS) is a rare and aggressive form of Cutaneous T-Cell Lymphoma (CTCL) characterised by a distinct metastatic pattern mainly involving blood and skin. Our expression analyses performed by microarrays demonstrated that many chemokines resulted up-regulated in this type of lymphoma. Since these chemoattractant molecules play a critical role in cellular recruitment and homing to tissues and in the metastatic process of several tumors, we focused our attention on one of them named CXCL13, a lymphoid chemokine involved in B-cell compartmental homing within secondary lymphoid organs. Peripheral Blood Mononuclear cells (PBMCs) were isolated from blood obtained from SS patients and controls by Ficoll-Hypaque density gradient centrifugation (Sigma Aldrich). SS cells and healthy resting CD4+ lymphocytes were purified by positive selection using an anti-human-CD4 conjugated dynabeads (Oxoid). Total RNA was extracted using the Trizol reagent (Life Technologies). Quantitative-Real Time RT-PCR analysis was performed on CD4+ sorted from 14 SS patients and 3 controls. CXCL13 primers were designed by means of the Primer Express software package (Applied Biosystems). The qRT-PCR were performed with a SYBR Green I dye chemistry and AmpliTaq Gold DNA Polymerase on an ABI PRISM 7000 machine (Applied Biosystems). Immunohistochemistry analyses for CXCL13 were performed on formalin-fixed, paraffin-embedded skin biopsies from 15 SS, 15 MF, 6 MF-B cell rich patients using streptoavidin-biotin peroxidase labeling method (DAKO). Sections were counterstained with hematoxylin. Plasma CXCL13 levels were determined using a CXCL13 ELISA kit (BD Pharmingen). Results can be summarized as follow: qRT-PCR analysis revealed that 6 out 13 of SS patients showed an high mRNA levels of CXCL13; Immunohistochemistry analysis showed that CXCL13 is abundantly expressed by neoplastic skin-infiltrating lymphocytes of 9 out 15 SS skin biopsies. Conversely, CXCL13 is weakly expressed on scattered neoplastic skin-infiltrating lymphocytes of 1 out 15 MF and 1 out 6 MF-B cell rich biopsies. Plasma CXCL13 concentrations in SS patients (n = 10) were 1362 ± 134 pg/mL. Conversely, those in MF patients (n = 10) and healthy donors (n = 5) were 70 ± 43 and 13 ± 10 pg/mL, respectively. Compared with healthy controls, plasma CXCL13 levels were significantly higher in patients with SS (p

Sézary Syndrome (SS) is a rare and aggressive form of Cutaneous T-Cell Lymphoma (CTCL) characterised by a distinct metastatic pattern mainly involving blood and skin and whose etiology and molecular pathogenesis are still unclear. Conventional cytogenetics studies have shown that most SS patients have chromosome aberrations; however allelotyping studies and genome-wide surveys for chromosome imbalances in this tumour are still very limited (Mao X. et al. 2003 Genes Chromosome Cancer 36:250–260). High-density single nucleotide polymorphism (SNP) arrays allow high-resolution and genome-wide detection of both loss of heterozygosity (LOH) and copy number (CN) abnormality. Therefore we used Affymetrix 10K SNP mapping array containing 11,560 tiled SNPs to investigate genomic aberrations of 13 individuals affected by SS. Genotype calls and signal information were obtained using GeneChip Operating Software (GCOS 1.4) and GeneChip DNA Analysis Software (GTYPE4.0). SNP calls were exported to be analysed with DNA-chip Analyser (dChip v1.3+) genotyping software which allows the simultaneous measurement of DNA copy number changes and LOH events (Zhao X. et al. 2004 Cancer Res. 64:3060–71; Lin M et al. 2004 Bioinformatics 20:1233–40). Our findings indicate that chromosomes 17p, 10/10q and 9 are most frequently affected by LOH events, while gains of CN were observed more often for chromosome 17q and 8/8q. Among our patients almost all individuals showing loss of the 17p arm have also gain of the 17q, suggesting the presence of the isochromosome 17q, a frequently reported abnormality in SS. In addition to this, we characterised the chromosome LOH pattern identifying seven regions of significant loss shared by multiple tumours. Sample clustering based on significant LOH regions identified two groups of patients: one of them consists of 4 patients with a lower rate of chromosomal losses while the other contains 9 patients mainly characterised by the co-occurrence of LOH at chromosome 17 and chromosome 10. The frequency and pattern of chromosomal changes in our group of 13 SS patients are in substantial agreement with previously described results using more conventional techniques, demonstrating the feasibility of the 10K SNP mapping array system to assess allelic imbalance in this tumour. The genome-wide approach and SNP high density allowed the identification of a larger number of LOH regions, including, however, those already described (chromosome 9p, 10q and 17p). Even though no significant statistical association can be observed due to the low number of cases available, we observed a lower overall survival in the group of 9 patients showing simultaneous LOH events at chromosome 17 and 10.

Sezary Syndrome (SS) is a rare form of Cutaneous T-Cell Lymphoma (CTCL) characterised by a distinct metastatic pattern mainly involving skin and blood. Chemokine and chemokine receptors have been implicated in the spreading process of many cancers including various forms of non-Hodgkin T-cell lymphomas (NHL). In this study we report that chemokine receptor CXCR4 is over-expressed by both circulating and skin-homing neoplastic T-lymphocytes of SS patients and is functionally active as demonstrated by the migration of freshly isolated Sezary (SzS) cells along the chemical gradient of its natural ligand SDF-1. To shed light on the regulation of CXCR4/SDF1 interaction, we also investigated the enzymatic activity of CD26/dipeptidylpeptidase IV (DPPIV) since SDF-1 is efficiently inactivated by CD26, in physiological condition.. This is of particular relevance because one of the hallmark of the circulating SzS cells is the loss of CD26 from the cell surface. We first demonstrated that the CD26 negative phenotype is similarly maintained also in the skin-homing neoplastic T lymphocytes; we then observed that the addition of exogenus soluble CD26 reduces the migratory response of SS cells to SDF-1 whereas the inhibition of the CD26 peptidase activity in Hut78, a CD26-positive CTCL cell line, enhances the SDF-1-induced migration of these cells. We finally showed that SS individuals exhibit a reduced activity of the soluble CD26 as revealed by the measurements performed on the patients derived plasma. Our findings suggest that the SDF-1-CXCR4 axis could play an important role in skin homing of SS through the regulatory activity of CD26.

We created a relational database of patients with cutaneous T-cell lymphoma (CTCL) to collect in a standardised fashion, anagraphic variables, clinical history, clinical, histological, haematological, and immunological information on CTCL patients hospitalised at IDI-IRCCS, Rome, Italy. At present, there are data on 424 patients, hospitalised from 1983 to July 2005. Active follow-up is performed yearly to ensure a standardised ascertainment of survival time. For deceased patients, the actual date of death (for all causes) is recorded, while surviving patients are censored at the date of last contact. The database includes 29 patients with Sezary syndrome (SS). Follow-up times ranged from 0 to 105 months. At first hospitalisation the median values of cells/mL were: white blood cells (WBC) 8750, neutrophils 4250, eosinophils 140, basophils 120, lymphocytes 2760, monocytes 500, CD3+ 2780, CD4+ 2431, CD8+ 192, CD19+ 96. Seventeen patients were deceased. We included in the Kaplan-Meier survival analysis only patients who were diagnosed before July 2004 (n=26). Median survival time from diagnosis was 52 months. No significant differences were observed in mortality for WBC (cutoff 9000 cells/uL), neutrophils (cutoff 4500 cells/uL), basophils (cutoff 200 cells/uL), lymphocytes (cutoff 3000 cells/uL), monocytes (cutoff 500 cells/uL), CD3+ (cutoff 2000 cells/uL), CD4+ (cutoff 2000 cells/uL), CD8+ (cutoff 200 cells/uL), CD19+ (cutoff 70 cells/uL). A lower survival was observed for patients with eosinophils Survival in patients with SS does not seem to be influenced by haemathologic parameters. However, patients with long-term survival (>90 months) are observed, and their characteristics should be further investigated. Survival analysis of 26 patients with Sézary syndrome, Rome, Italy, 1991–2004. Survival analysis of 26 patients with Sézary syndrome, Rome, Italy, 1991–2004.

Anti-thymocyte globulin (ATG) provides effective therapy for many patients with aplastic anemia, and its mechanism of action has been presumed to be secondary to lymphocytotoxicity. However, our studies of lymphocyte function in aplastic anemia show marked abnormalities of lymphokine production, which ATG may modulate. In 12 of 17 patients with aplastic anemia, interleukin 2 (IL2) production was markedly elevated in vitro (P less than .01 by paired statistical analysis). Expression of the IL2 receptor, or Tac antigen, on peripheral lymphocytes assessed by flow microfluorometry was also increased above the normal range in 11 of 15 cases. Studies of ATG suggested that it might act to stimulate lymphocyte function. In vitro, ATG is a mitogen, as measured by incorporation of 3H-thymidine into blood mononuclear cells; the response of cells to ATG from patients with aplastic anemia was exaggerated in comparison with normals. Cell proliferation was accompanied by production of IL2 to levels that were, in some cases, similar to those obtained with lectin stimulation. Finally, supernatants from lymphocytes cultured in the presence of ATG were able to replace adherent cells in providing growth factors for the support of nonadherent cells in methylcellulose hematopoietic colony assays. These results provide a mechanism for an “immunostimulatory” action of ATG in effecting hematopoietic response in some patients with aplastic anemia.

Anti-thymocyte globulin (ATG) provides effective therapy for many patients with aplastic anemia, and its mechanism of action has been presumed to be secondary to lymphocytotoxicity. However, our studies of lymphocyte function in aplastic anemia show marked abnormalities of lymphokine production, which ATG may modulate. In 12 of 17 patients with aplastic anemia, interleukin 2 (IL2) production was markedly elevated in vitro (P less than .01 by paired statistical analysis). Expression of the IL2 receptor, or Tac antigen, on peripheral lymphocytes assessed by flow microfluorometry was also increased above the normal range in 11 of 15 cases. Studies of ATG suggested that it might act to stimulate lymphocyte function. In vitro, ATG is a mitogen, as measured by incorporation of 3H-thymidine into blood mononuclear cells; the response of cells to ATG from patients with aplastic anemia was exaggerated in comparison with normals. Cell proliferation was accompanied by production of IL2 to levels that were, in some cases, similar to those obtained with lectin stimulation. Finally, supernatants from lymphocytes cultured in the presence of ATG were able to replace adherent cells in providing growth factors for the support of nonadherent cells in methylcellulose hematopoietic colony assays. These results provide a mechanism for an “immunostimulatory” action of ATG in effecting hematopoietic response in some patients with aplastic anemia.