Search

The GIMEMA phase II LLC1518 VERITAS trial investigated the efficacy and safety of frontline, fixed-duration venetoclax and rituximab (VenR) combination in young (≤65 years) and fit patients with chronic lymphocytic leukemia (CLL) and unmutated IGHV and/or TP53 disruption. Treatment consisted of the Ven ramp-up, six-monthly courses of the VenR combination, followed by six monthly courses of Ven single agent. A centralized assessment of measurable minimal residual disease (MRD) was performed on the peripheral blood (PB) and bone marrow (BM) by ASO-PCR at the end of treatment (EOT) and during the follow-up. The primary endpoint was the complete remission (CR) rate at the EOT. Seventy-five patients were enrolled; the median age was 54 years (range 38-65), 96% had unmutated IGHV, 9 (12%) had TP53 disruption, and 4% were IGHV mutated with TP53 disruption. The overall response rate (ORR) at the EOT was 94.7%, with a CR rate of 76%. An undetectable (u) MRD was recorded in 69.3% of patients in the PB and 58.7% in the BM. The 12-month MRD-free survival in the 52 patients with uMRD in the PB at the EOT was 73.1%. After a median follow-up of 20.8 months, no disease progressions were observed. Three patients have died, two due to Covid-19 and 1 to tumor lysis syndrome. The first report of the VERITAS study shows that frontline VenR was associated with a high rate of CRs and durable responses with uMRD in young patients with CLL and unfavorable genetic characteristics.

The evaluation of the somatic hypermutation of the clonotypic immunoglobulin heavy variable gene has become essential in the therapeutic management in chronic lymphocytic leukemia patients. European Research Initiative on Chronic Lymphocytic Leukemia promotes good practices and standardized approaches to this assay but often they are labor-intensive, technically complex, with limited in scalability. The use of next-generation sequencing in this analysis has been widely tested, showing comparable accuracy and distinct advantages. However, the adoption of the next generation sequencing requires a high sample number (run batching) to be economically convenient, which could lead to a longer turnaround time. Here we present data from nanopore sequencing for the somatic hypermutation evaluation compared to the standard method. Our results show that nanopore sequencing is suitable for immunoglobulin heavy variable gene mutational analysis in terms of sensitivity, accuracy, simplicity of analysis and is less time-consuming. Moreover, our work showed that the development of an appropriate data analysis pipeline could lower the nanopore sequencing error rate attitude.

Ibrutinib represents extraordinary progress in the treatment of chronic lymphocytic leukemia (CLL). However, treatment-related adverse events limit the benefit of this agent. This observational, multicenter study focused on the incidence, risk factors, and prognostic impact of infections in 494 patients with CLL treated with an ibrutinib-based treatment. Ibrutinib was given to 89 (18%) previously untreated patients (combined with rituximab, 24) and 405 (82%) relapsed/refractory patients. Pneumonia (PN), grade ≥3 non-opportunistic infections (NOI), and opportunistic infections (OI) were recorded in 32% of patients with an overall incidence rate per 100 person-year of 15.3% (PN, 10%, NOI, 3.3%, OI, 2%). Infections were the reason for the permanent discontinuation of ibrutinib in 9% of patients. Patients who experienced pneumonia or a severe infection showed a significantly inferior survival than those who were infection-free (p &lt, 0.0001). A scoring system based on the three factors associated with a significant and independent impact on infections—PN or severe infection in the year before starting ibrutinib, chronic obstructive pulmonary disease, ≥2 prior treatments—identified patients with a two- to threefold increase in the rate of infections. In conclusion, the results of this study highlight the adverse impact of infectious events on the outcomes of CLL patients treated with ibrutinib.

We report a customized gene panel assay based on multiplex long-PCR followed by third generation sequencing on nanopore technology (MinION), designed to analyze five frequently mutated genes in chronic lymphocytic leukemia (CLL): TP53, NOTCH1, BIRC3, SF3B1 and MYD88. For this purpose, 12 patients were selected according to specific cytogenetic and molecular features significantly associated with their mutational status. In addition, simultaneous analysis of the targets genes was performed by molecular assays or Sanger Sequencing. Data analysis included mapping to the GRCh37 human reference genome, variant calling and annotation, and average sequencing depth/error rate analysis. The sequencing depth resulted on average higher for smaller amplicons, and the final breadth of coverage of the panel was 94.1%. The error rate was about 6% and 2% for insertions/deletions and single nucleotide variants, respectively. Our gene panel allows analysis of the prognostically relevant genes in CLL, with two PCRs per patient. This strategy offers an easy and affordable workflow, although further advances are required to improve the accuracy of the technology and its use in the clinical field. Nevertheless, the rapid and constant development of nanopore technology, in terms of chemistry advances, more accurate basecallers and analysis software, offers promise for a wide use of MinION in the future.

To assess the predictive power of the comet assay in the context of occupational exposure to pesticides.The recruited subjects completed a structured questionnaire and gave a blood sample. Exposure to pesticides was measured by means of an algorithm based on Dosemeci's work (Agricultural Health Study). Approximately 50 images were analyzed for each sample via fluorescence microscopy. The extent of DNA damage was estimated by tail moment (TM) and is the product of tail DNA (%) and tail Length.Crude significant risks (odds ratios, ORs) for values higher than the 75th percentile of TM were observed among the exposed subjects (score 1). The frequency of some confounding factors (sex, age and smoking) was significantly higher among the exposed workers. A significant dose-effect relationship was observed between TM and exposure score. Significant high-risk estimates (ORs), adjusted by the studied confounding factors, among exposure to pesticides and TM, % tail DNA and tail length were confirmed using unconditional logistic regression models.The adjusted associations (ORs) between the comet parameters and exposure to pesticides were significant. The sensitivity of the comet test was low (41%), the specificity (89%) and the predictive positive value (0.77) were found acceptable.

Patients with hematological malignancies (HM) undergoing hematopoietic stem cell transplantation (HSCT) have an increased vulnerability to SARS-Cov-2 (Sharma et al, Lancet Haematology 2020; Ljungman et al, Leukemia 2021), the reason why international guidelines strongly support the need for a protective vaccination for these subjects. The most relevant data currently available on the response to a complete anti-SARS-Cov-2 vaccination cycle in HM patients after HSCT refer to 314 patients reported in a Lithuanian national survey (Maneikis et al, Lancet Haematol 2021). In this study, the median titers of antibodies against SARS-Cov-2, determined 7-21 days after the second vaccination, were comparable to that of healthy controls (HC) in both autologous and allogeneic groups, with no patient found below the protective threshold of 50 arbitrary units (AU)/ml. Notably, the large majority of patients had received the transplant more than 1 year before vaccination. In a prospective, cohort study, we compared 114 patients, who had received an autologous or allogeneic HSCT at least three months before the first dose of vaccination, to 107 HC, matched for age and sex. Study population and HC received two doses of BNT162b2 anti-SARS-Cov-2 mRNA vaccine on days 1 and 21, between April and May 2021. Serological tests were performed by a commercially available immunoassay for the quantitative determination of anti-spike IgG antibodies to SARS-Cov-2. The cut-off for defining responders was 50 or greater AU/ml. Patients and HC samples were collected four weeks after the second dose of the vaccine. Table 1 reports the main clinical characteristics of patients and HC. Eighteen of 114 patients (16%) did not respond (24% in the allogeneic group, 6% in autologous recipients). Overall, median antibodies titers did not differ between HC and the entire cohort of transplanted patients, recipients of allogeneic HSCT, all patients responding to the vaccine or responders in the autologous subgroup (Figure 1A). All autologous HSCT recipients had significantly lower titers of antibodies than HC, while higher levels were found in responders who had received allogeneic HSCT (Figure 1A). Responders in the allogeneic subgroup showed antibodies titers significantly higher than responders in the autologous subgroup (Figure 1B). We further stratified patients in three groups, according to the time elapsed from transplant to vaccination: G1:5 years. Higher antibodies titers were observed in HC compared to all transplanted patients in G1 (Figure 1C), including both allogeneic (Figure 1D) and autologous (Figure 1E) HSCT recipients. No differences emerged in G2 between HC and all patients (Figure 1C), allogeneic (Figure 1D) or autologous (Figure 1E) HSCT recipients. Finally, no differences were found in G3 when comparing HC with all patients (Figure 1C) or allogeneic recipients (Figure 1D), whereas patients in the autologous subgroup showed significantly lower titers than HC (Figure 1E). Myeloma patients with controlled disease showed higher titers than patients with active disease (Figure 1F). According to median age, autologous HSCT recipients older than 57 years had significantly lower antibody levels than younger patients (Figure 1G). Autologous vs allogeneic HSCT, age of all patients and of allogeneic HSCT recipients, sex, type of allogeneic HSCT, conditioning regimen, age and sex of donor, occurrence of GVHD, disease type and single vs double autologous HSCT did not significantly impact on antibody levels (data not shown). No relevant side effects were recorded after vaccination. With a median follow up of 12 weeks, no case of COVID19 occurred among vaccinated patients. In our single center study, patients with a previous history of HSCT tolerated well BNT162b2 vaccine and mounted a potentially protective immune response in the majority of cases one month after two doses of vaccine. However, lack of response was not rare, especially in the allogeneic setting. The main factor associated with the quality of response was the time from HSCT, with lower responses within the first year from transplant and differences between autologous and allogeneic groups transplanted more than five years before vaccination. Here, a consolidated, complete immune reconstitution in allogeneic HSCT recipients, as well as age and a still active disease in the autologous setting, could have played opposite pivotal roles. Figure 1 Figure 1. Disclosures Delia: Gilead: Consultancy; Amgen: Consultancy; abbvie: Consultancy; Jazz pharmaceuticals: Consultancy.

Background Occupational exposure is known to play a role in the aetiology of lymphomas. The aim of the present work was to explore the occupational risk of the major B-cell lymphoma subtypes using a case–control study design. Methods From 2009 to 2014, we recruited 158 lymphoma cases and 76 controls in the provinces of Bari and Taranto (Apulia, Southern Italy). A retrospective assessment of occupational exposure based on complete work histories and the Carcinogen Exposure (CAREX) job-exposure matrix was performed. Results After adjusting for major confounding factors, farmers showed an increased risk of diffuse large B-cell lymphoma (DLBCL) [odds ratio (OR) = 10.9 (2.3–51.6)] and multiple myeloma (MM) [OR = 16.5 (1.4–195.7)]; exposure to the fungicide Captafol was significantly associated with risk of non-Hodgkin lymphoma (NHL) [OR = 2.6 (1.1–8.2)], particularly with the risk of DLBCL [OR = 5.3 (1.6–17.3)]. Conclusions Agricultural activity seems to be a risk factor for developing lymphoma subtypes, particularly DLBCL, in the provinces of Bari and Taranto (Apulia Region, Southern Italy). Exposure to the pesticides Captafol, Paraquat and Radon might be implicated. Trial registration Protocol number UNIBA 2207WEJLZB_004 registered 22/09/2008.

Background Occupational exposure is known to play a role in the aetiology of lymphomas. The aim of the present work was to explore the occupational risk of the major B-cell lymphoma subtypes using a case–control study design. Methods From 2009 to 2014, we recruited 158 lymphoma cases and 76 controls in the provinces of Bari and Taranto (Apulia, Southern Italy). A retrospective assessment of occupational exposure based on complete work histories and the Carcinogen Exposure (CAREX) job-exposure matrix was performed. Results After adjusting for major confounding factors, farmers showed an increased risk of diffuse large B-cell lymphoma (DLBCL) [odds ratio (OR) = 10.9 (2.3–51.6)] and multiple myeloma (MM) [OR = 16.5 (1.4–195.7)]; exposure to the fungicide Captafol was significantly associated with risk of non-Hodgkin lymphoma (NHL) [OR = 2.6 (1.1–8.2)], particularly with the risk of DLBCL [OR = 5.3 (1.6–17.3)]. Conclusions Agricultural activity seems to be a risk factor for developing lymphoma subtypes, particularly DLBCL, in the provinces of Bari and Taranto (Apulia Region, Southern Italy). Exposure to the pesticides Captafol, Paraquat and Radon might be implicated. Trial registration Protocol number UNIBA 2207WEJLZB_004 registered 22/09/2008.

Classical Hodgkin lymphoma (cHL) is characterized by the presence of tumoral cells in a rich background of T and B cells, macrophages and other inflammatory cells. The contribution of these non-tumoral cells to the pathogenesis of HL is still poorly understood. In our study we evaluated the prognostic significance of peripheral blood B, T and natural killer (NK) cells at diagnosis in 118 immunocompetent patients with cHL treated at our institution between January 2006 and December 2010. Fifty-four (46%) were male and 64 (54%) female. Median age at diagnosis was 33 years (range 15-82), and 71 patients (60%) presented an advanced stage (IIB-IV), 54 (46%) had bulky disease and 55 (47%) presented B symptoms. At the end of treatment, 94 patients (80%) had a complete response (CR) and 24 (20%) had a partial response. After a median follow-up of 54 months, 18 patients (15%) had relapsed. The variables that had a negative impact on progression-free survival (PFS) at univariate analysis were advanced stage, bone marrow involvement, International Prognostic Score (IPS) ≥ 3, positive interim positron emission tomography (int-PET), NK cells < 200/μL, CD19 cells < 85/μL, CD3/CD19 ratio ≥ 13 and CD4/CD19 ratio ≥ 10. At multivariate analysis, advanced stage, positive int-PET and CD4/CD19 ratio ≥ 10 were independent prognostic factors of PFS. New biological markers could be predictive of the response to treatment and survival in cHL. A CD4/CD19 ratio ≥ 10 seems to be associated with a worse outcome.

Background The assessment of TP53 mutational status is becoming a routine clinical practice for chronic lymphocytic leukemia patients (CLL). A broad spectrum of molecular techniques has been employed so far, including both direct Sanger sequencing and next generation sequencing. Oxford Nanopore Technologies recently released the MinION an USB-interfaced sequencer. In this paper we report our experience, with the MinION technology for the detection of the TP53 gene mutation in CLL patients. Twelve CLL patients at diagnosis were included in this study. All except one patient showed the TP53 gene deletion in Fluorescence in situ hybridization experiments. Patients were investigated for TP53 mutation by Sanger and by MinION sequencing. Analysis by Sanger was performed according with the IARC protocol. Analysis by MinION was performed adopting a strategy based on long template PCR, read error correction, and post variant calling filtering. Results Due to the high error rate of nanopore technology, sequence data were both used directly and before correction with two different in silico methods: ALEC and nanocorrect. A mean error rate of 15 % was detected before correction that was reduced to 4-5 % after correction. Analysis by Sanger sequencing was able to detect four patients mutated for TP53. MinION analysis detected one more mutated patient previously not detected from Sanger. Conclusion In our hands, the Nanopore technology shows correlation with Sanger sequencing but more sensitive, manageable and less expensive, and therefore has proven to be a useful tool for TP53 gene mutation detection. Electronic supplementary material The online version of this article (doi:10.1186/s13000-016-0550-y) contains supplementary material, which is available to authorized users.

Introduction: The study of oxidative stress induced in peripheral lymphocytes by aneuploidizzanti substances may be useful to identify biological markers that predict malignancy and evaluate repair...

Recently, encouraging results in terms of safety and efficacy have been obtained using bendamustine–rituximab (BR) in untreated chronic lymphocytic leukaemia (CLL) patients enrolled in a phase II study. Here, we report a retrospective international multicenter study of CLL patients treated with BR as front-line therapy. The cohort included 279 patients with progressive CLL from 33 centers (29 Italian, 3 Israeli and 1 German) who received at least 1 cycle of BR as first-line treatment during the 2008–2014 period. The primary objective of this study was to evaluate the efficacy and safety of BR administered as front-line therapy, outside of controlled clinical trials. Median age was 70 years (range, 43–86 years); 62.4% were males and 35.8% had Binet stage C. Forty-two patients (15.2%) were unfit (cumulative illness rating scale [CIRS] score ≥7), and 140 (50.2%) had creatinine clearance ≤70 ml/min. Fluorescent in situ hybridisation analysis, available for 192 cases, showed that 21 (10.9%) had del11q and 18 (9.4%) del17p. The overall response rate (ORR) was 86.4%, with a complete remission rate of 28%. Patients with del17p had an ORR of 66.7%. After median follow-up of 24 months, the 2-year progression-free survival (PFS) was 69.9%; CIRS ≥7, immunoglobulin heavy-chain variable-region (IGHV) unmutated status, del17p and BR dose intensity

The aim of this study was to evaluate the impact of clinical variables and biologic features on response rate (RR), overall survival (OS) and progression-free survival (PFS) in 111 patients with de novo diffuse large B cell lymphoma (DLBCL). Fifty-three patients were treated with CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) and 58 patients were treated with R-CHOP (rituximab + CHOP). The variables predictive of RR in the CHOP group were B symptoms, age, clinical stage, bone marrow involvement, bulky disease, International Prognostic Index (IPI) and Bcl-2; in the R-CHOP group, these variables were bulky disease, bone marrow involvement, IPI and Ki67 expression >80%. Multivariate analysis showed that in patients treated with CHOP, the independent prognostic factors associated with PFS were age, bulky disease, IPI and Bcl-2 and those associated with OS were performance status, clinical stage, IPI and bone marrow involvement. In contrast, in patients treated with R-CHOP, the variable shown by multivariate analysis to be an independent prognostic factor associated with PFS was bulky disease, whereas Ki67 expression >80% was associated with OS and PFS. Our data show that a high Ki67 expression and bulky disease could represent possible predictive factors of poor prognosis, which would help to identify a high-risk subgroup of newly diagnosed DLBCL.

Primary central nervous system non-Hodgkin lymphomas (PCNSNHL) are extranodal lymphomas arising within and confined to the central nervous system (CNS). A frequency of 1 – 3% of all non-Hodgkin lym...

Recurrences of Hodgkin's Lymphoma (HL) 5 years after the initial therapy are rare. The aim of this study is to report a single centre experience of the clinical characteristics, outcome, and toxicity of pts who experienced very late relapses, defined as relapses that occurred 5 or more years after the achievement of first complete remission. Of 532 consecutive pts with classical HL treated at our Institute from 1985 to 1999, 452 pts (85%) achieved a complete remission. Relapse occurred in 151 pts: 135 (29.8%) within 5 years and 16 over 5 years (3.5%, very late relapses). Very late relapses occurred after a median disease-free interval of 7 years (range: 5–18). Salvage treatment induced complete remission in 14 pts (87.5%). At a median of 4 years after therapy for very late relapse, 10 pts (63%) are still alive and free of disease and 6 (37%) died (1 from progressive HL, 1 from cardiac disease, 1 from thromboembolic disease, 1 from HCV reactivation, and 2 from bacterial infection). The probability of failure-free survival at 5 years was 75%. The majority of deaths are due to treatment-related complications. Therapy regimens for very late relapse HL are warranted to minimize complications.

Abstract 2030 Background: The therapeutic efficacy of allogeneic stem cell transplantation (alloSCT) for hematological malignancies relies largely on the graft versus leukemia (GvL) effect exerted by the donor CD3 cells, but an uncontrolled graft-versus-host-disease (GvHD) bears a risk of complications. On the other hand, T regs cells (CD4+CD25high Foxp3+) are believed to maintain tolerance and to inhibit GvHD after alloSCT; also, the Foxp3 gene encodes a transcription factor that is a key for thymic development, so T regs cells could preserve an optimal microenviroment for the reconstitution of functional immunity after alloSCT. Moreover, when looking at post allotransplant patients' outcomes, while it is largely known the impact of acute GVHD (triggered by CD3 donor T cells) on survival, there is no evidence that donor graft CD3/T regs ratio may determine an effect in terms of OS, NRM and relapse free survival rates so far. Patients and Methods: In this study we analyzed the graft CD3+/Tregs ratio (gCD3/Tregs R) and determined its impact on acute GVHD (aGVHD), immunological recovery and survival rates (OS, NRM and Relapse) after myeloablative alloPBSCT. We analyzed 74 consecutive patients transplanted with unmanipulated peripheral blood stem cells from an HLA identical related donor (n=48) or an HLA identical unrelated donor (n=26); diagnoses were acute myeloid leukaemia (n=62), acute lymphoblastic leukaemia (n=13). The median CD3+ and Tregs dose administered was 238 (range (r): 67–550) and 12,5×106̂/Kg (r: 2–21), respectively; the median gCD3/Tregs R was 19 (r: 8–250). Patients were subdivided into a high gCD3/Tregs R (>=36) group (HR group n= 30) and a low gCD3/Tregs R ( Results: The incidence of aGVHD (grade II-IV) in the low gCD3/Tregs R (LR) group was lower than in the high gCD3/Tregs R (HR) group (4/30 or 13% vs 36/44 or 82%, p Conclusions: Taken together, our data may suggest that Tregs content is able to mediate protective effects against aGVHD, while preserving GvL effects as demonstrated by relapse rate comparison between H and LR groups. However, larger studies are needed to understand the real contribution of gCD3/Tregs R on survival rates. Disclosures: No relevant conflicts of interest to declare.

Abstract 4892 Introduction Mantle cell lymphoma (MCL) is a distinct B cell non Hodgkin lymphoma characterized by CD 5 expression, t (11; 14)(q13; q32) translocation and over-expression of Cyclin D1, and frequently has an aggressive clinical course. There is no standard of care for the treatment of MCL. Current treatment approaches are non curative and pts median survival is 4–6 years. Various studies have reported promising results for a high dose Cytarabine-containing regimen in the treatment of MCL. Fludarabine has also been recognized as effective treatment in pts with MCL, either as a single agent or in combination with other drugs. The addition of Rituximab improves the response to the treatment. The aim of this study is to assess the efficacy and toxicity of a combination of Fludarabine, Aracytine and Rituximab treatment in refractory and relapsed MCL. Methods We retrospectively evaluated 20 pts with refractory or relapsed MCL treated in our institution between February 2007 and February 2010. Median age was 59 yrs (54-77 yrs), 14 pts (70%) were males, 18 pts (90 %) had stage IV, 16 pts (80%) had bone marrow involvement, 16 (80%) presented comorbidities. Eight pts (40%) were in first relapse, 12 (60%) in second relapse. Twelve pts (60%) had a “Mantle Cell Lymphoma International Prognostic Index” (MIPI) score ≥ 7. Therapy included: fludarabine 25 mg/m2/daily intravenously for 3 days, aracytine 500 mg/m2/daily for 3 days and Rituximab 375 mg/m2/daily for 1 day, Dexamethasone 8 mg daily for 3 days, every 28 days for 4 cycles. Results Eight pts (40%) achieved complete response (CR) and 4 pts (20%) a Partial Remission (PR) with an overall response rate (ORR) of 60%. Eight pts (40%) progressed and one of them died of active disease. After a median follow up of 17 months (range 8–36), OS is 70% and PFS is 55%. Toxicity was mainly hematological with grade >=3 neutropenia in 40 (50%) of the 80 cycles performed, grade >=2 anemia in 30 (37%) and grade 4 thrombocytopenia in 24 (30%). In 16 (20%) cycles pts required red blood cells transfusions, in 12 (15%) platelet transfusions. One episode of Herpes Zoster infection was observed. Conclusions This study suggests that the combination of Fludarabine, Aracytine and Rituximab appears to be an effective regimen with a promising response rate and manageable toxicity, for pretreated pts often affected by comorbidities and with poor prognosis. Further studies are needed to assess the efficacy of this combination therapy and to further test the role of this approach in MCL. Disclosures: No relevant conflicts of interest to declare.

Abstract 4703 The World Health Organization (WHO) recently published a revised, updated edition of the WHO Classification of Tumours of the Haematopoietic and Lymphoid Tissues, including new criteria for the recognition of some previously described neoplasms as well as clarification and refinement of the defining criteria for others. It also adds entities – some defined mainly by genetic and immunophenotypic features – that have only recently been characterized. Particularly, the diagnosis and classification of acute leukemias of ambiguous lineage is debated; among these: “blastic NK-cell lymphoma” and “agranular CD4+/CD56+ hematodermic neoplasms”. Both of them are now known to be, in virtually all cases, a tumor derived from precursors of a specialized subset of dendritic cells, plasmacytoid dendritic cells, and so are myeloid-related neoplasms defined as blastic plasmacytoid dendritic cell neoplasm (BPDCN). This is a clinically aggressive neoplasm that is usually characterized at onset by solitary or multiple skin lesions, often with associated regional lymphadenopathy, and frequently by involvement of the PB and BM. Leukemic cells show submembranous cytoplasmic vacuoles and pseudopodia-like extensions of agranular cytoplasm. The blasts in such cases do not express myeloperoxidase or nonspecific esterase, and are characterized by the expression of CD4, CD43, CD56, CD123, BDCA-2/CD303, TCL1, and CLA; CD7 and CD33 are not uncommonly expressed as well, and TdT is expressed in about 30% of cases. There is no expression of CD34 or CD117. Here we report three cases with clinical data, cytological and immunophenotypic findings strongly suggesting the diagnosis of BPDCN. Case 1 An 80 year-old-man was admitted to our institution on December 2006. He referred the occurrence of skin lesions since January 2005, when a diagnosis of extranodal B-cell non-Hodgkin lymphoma was made and treatment with conventional chemotherapy was performed, but without achieving any response. At our evaluation he presented leukocytosis (144 × 109/L) associated with purplish, firm nodules on the trunk, arms and face. Peripheral blood and bone marrow aspirate showed the presence of blast cells with a lymphoid appearance, granular periodic acid-Schiff (PAS) positivity and a high expression of CD33, CD4, and CD56. He was treated with AML-like therapy, but died of disease progression. Case 2 A 79-year old woman was admitted in December 2006 with a 2-month history of anemia, splenomegaly, and weight loss of 10 kg in the last year. Laboratory tests were as follows: Hb, 41 g/L; leukocytes, 2.5 × 109/L (with 10% of blast cells); platelets, 43 × 109/L. No lymphadenopathy or skin lesions were present. Bone marrow examination revealed 41% of small to medium-sized blast cells without Auer rods or granula and negative reactivity to myeloperoxidase, esterase and PAS. She was treated with an AML-like protocol; she achieved partial response, but died after three months, of disease progression. Case 3 A 69-year-old man was admitted to our Institution for cytopenia in June 2009. He referred the occurrence of brownish-purple firm nodules on the trunk since April 2009. At our evaluation he presented pancytopenia; bone marrow aspiration was performed and revealed infiltration by 65% of blasts with reticulated chromatin, evident nucleoli, a vacuolated cytoplasm and pseudopodia-like expansions. The blasts were negative for myeloperoxidase, monocyte esterase and PAS staining. Skin biopsy revealed a dermal infiltration by the same blastic-cell BM population. He underwent AML-like therapy and, although the skin lesions disappeared, 30% blastic bone marrow infiltration persisted. Morphological revision of these cases, selected for their peculiar immunophenotype reported in the following Table, revealed the same cytological features and cytochemical reactivity in cases 2 and 3; case 1 had a lymphoblastic-like morphology and showed PAS positivity, but the lack of cCD3 was not consistent with the diagnosis of ALL. All the cases were FLT3-ITD+. We suggest that a correct modern panel of MoAb with a careful morphological examination could help to pose the diagnosis of BPDCN, which typically affects older patients and is characterized by poor prognosis. Disclosures: No relevant conflicts of interest to declare.

Recovery of cytomegalovirus (CMV)-specific CD8+ T cells after allogeneic stem cell transplantation (SCT) is critical for protection against CMV infection and disease. Moreover, Foxp3+CD4+CD25high regulatory T cells (Tregs) are a major regulator of adaptive immunity, preventing graft-versus-host disease (GVHD) and so promoting timely and complete immune recovery. The aim of our study was to evaluate the recovery of circulating tetramer-based CMV-specific CD8+ T cells and T regs in 46 patients after allogeneic peripheral blood SCT (PBSCT). CMV infection and/or disease was observed in 7% and 94% of patients with or without CMV-specific CD8+ T cells recovery (P < .001), and in 77% and 4% of patients with or without acute GVHD (aGVHD) (P < .001), respectively. T regs values were higher in patients without than with CMV infection and/or disease at 2 (P < .001) and 3 months (P < .001) after allogeneic PBSCT, respectively. Moreover, we observed a positive correlation between T regs and the recovery of CMV-specific CD8+ T cells at 2 (r = .61, P < .0001) and 3 (r = .72, P < .00001) months, respectively. Tregs were higher in patients without than with aGVHD at 1, 2 (P < .001) and 3 months (P < .0001), respectively. At multivariate logistic regression, aGVHD (odds ratio [OR]: 2.60, 95% confidence interval [CI] [1.3-5.0], P = .0006) and CMV-specific CD8+ T cells recovery (OR:2.25, 95% CI [1.2-4.8], P = .05) were correlated with CMV infection and/or disease, whereas no correlation was found for Tregs, absolute neutrophil count, patients' and donors' age, disease status pretransplantation, type of disease, and CMV serology. Taken together, our data may suggest the existence of a correlation between Tregs and the recovery of CMV-specific CD8+ T cells; Tregs may preserve an optimal microenvironment for the reconstitution of functional immunity and mediate protective effects against aGVHD.