Search

Background Hairy cell leukemia (HCL) is a rare chronic B cell malignancy, characterized by infiltration of bone marrow, blood and spleen by typical “hairy cells” that bear the BRAFV600E mutation. However, in addition to the intrinsic activation of the MAP kinase pathway as a consequence of the BRAFV600E mutation, the potential participation of other signaling pathways to the pathophysiology of the disease remains unclear as the precise origin of the malignant hairy B cells. Materials and methods Using mRNA gene expression profiling based on the Nanostring technology and the analysis of 290 genes with crucial roles in B cell lymphomas, we defined a 17 gene expression signature specific for HCL. Results Separate analysis of samples from classical and variant forms of hairy cell leukemia showed almost similar mRNA expression profiles apart from overexpression in vHCL of the immune checkpoints CD274 and PDCD1LG2 and underexpression of FAS. Our results point to a post-germinal memory B cell origin and in some samples to the activation of the non-canonical NF-κB pathway. Conclusions This study provides a better understanding of the pathogenesis of HCL and describes new and potential targets for treatment approaches and guidance for studies in the molecular mechanisms of HCL.

International audience; Prolonged Covid-19 is an emerging issue for patients with lymphoma or immune deficiency. We aimed to examine prolonged length of in-hospital stay (LOS) due to Covid-19 among patients with lymphoma and assess its determinants and outcomes. Adult patients with lymphoma admitted for Covid-19 to 16 French hospitals in March and April, 2020 were included. Length of in-hospital stay was analyzed as a competitor vs death. The study included 111 patients. The median age was 65 years (range, 19–92). Ninety-four patients (85%) had B-cell non-Hodgkin lymphoma. Within the 12 months prior to hospitalization for Covid-19, 79 patients (71%) were treated for their lymphoma. Among them, 63 (57%) received an anti-CD20 therapy. Fourteen patients (12%) had relapsed/refractory disease. The median LOS was 14 days (range, 1–235). After a median follow-up of 191 days (3–260), the 6-month overall survival was 69%. In multivariable analyses, recent administration of anti-CD20 therapy was associated with prolonged LOS (subdistribution hazard ratio 2.26, 95% confidence interval 1.42–3.6, p < 0.001) and higher risk of death (hazard ratio 2.17, 95% confidence interval 1.04–4.52, p = 0.039). An age ≥ 70 years and relapsed/refractory lymphoma were also associated with prolonged LOS and decreased overall survival. In conclusion, an age ≥ 70 years, a relapsed/refractory lymphoma and recent administration of anti-CD20 therapy are risk factors for prolonged LOS and death for lymphoma patients hospitalized for Covid-19. These findings may contribute to guide the management of lymphoma during the pandemic, support evaluating specific therapeutic approaches, and raise questions on the efficacy and timing of vaccination of this particular population.

IntroductionThis study aims to define the phenotypic and molecular spectrum of the two clinical forms of β-galactosidase (β-GAL) deficiency, GM1-gangliosidosis and mucopolysaccharidosis IVB (Morquio disease type B, MPSIVB).MethodsClinical and genetic data of 52 probands, 47 patients with GM1-gangliosidosis and 5 patients with MPSIVB were analysed.ResultsThe clinical presentations in patients with GM1-gangliosidosis are consistent with a phenotypic continuum ranging from a severe antenatal form with hydrops fetalis to an adult form with an extrapyramidal syndrome. Molecular studies evidenced 47 variants located throughout the sequence of the GLB1 gene, in all exons except 7, 11 and 12. Eighteen novel variants (15 substitutions and 3 deletions) were identified. Several variants were linked specifically to early-onset GM1-gangliosidosis, late-onset GM1-gangliosidosis or MPSIVB phenotypes. This integrative molecular and clinical stratification suggests a variant-driven patient assignment to a given clinical and severity group.ConclusionThis study reports one of the largest series of b-GAL deficiency with an integrative patient stratification combining molecular and clinical features. This work contributes to expand the community knowledge regarding the molecular and clinical landscapes of b-GAL deficiency for a better patient management.

Immunocompromised individuals such as patients with chronic lymphocytic leukemia (CLL) are at risk of impaired immune responses to vaccination. The objective of our study was to evaluate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific antibody responses in patients with CLL after the first, second, and third doses of the BNT162b2 or mRNA-1273 vaccines and after a single dose for patients with confirmed previous COVID-19. In all, 530 patients were included in the study. Patients received 2 doses at a 4-week interval and a third dose if they were seronegative after the second dose. Response rate was 27% after dose 1 and 52% after dose 2. Post-dose 2 treatment-naïve patients had the highest response rate (72%) followed by patients previously treated by chemoimmunotherapy (60%). Among patients receiving therapy, those receiving Bruton tyrosine kinase inhibitor alone (22%) or in combination with anti-CD20 monoclonal antibodies or venetoclax (0%) had the poorer response rate whereas patients who received venetoclax monotherapy achieved a significantly higher response rate (52%). A multivariable analysis identified age older than 65 years, ongoing CLL treatment, and gamma globulin ≤6 g/L as independent predictors of the absence of seroconversion. Post-dose 2 seronegative patients had a global response rate of 35% after dose 3. This study provides an argument for the use of a third dose and for prophylactic SARS-CoV-2 neutralizing monoclonal antibodies.

International audience; The etiopathogenesis of critical COVID-19 remains unknown. Indeed given major confounding factors (age and comorbidities), true drivers of this condition have remained elusive. Here, we employ an unprecedented multi-omics analysis, combined with artificial intelligence, in a young patient cohort where major comorbidities have been excluded at the onset. Here, we established a three-tier cohort of individuals younger than 50 years without major comorbidities. These included 47 “critical” (in the ICU under mechanical ventilation) and 25 “non-critical” (in a non-critical care ward) COVID-19 patients as well as 22 healthy individuals. The analyses included whole-genome sequencing, whole-blood RNA sequencing, plasma and blood mononuclear cells proteomics, cytokine profiling and high-throughput immunophenotyping. An ensemble of machine learning, deep learning, quantum annealing and structural causal modeling led to key findings. Critical patients were characterized by exacerbated inflammation, perturbed lymphoid/myeloid compartments, coagulation and viral cell biology. Within a unique gene signature that differentiated critical from non-critical patients, several driver genes promoted critical COVID-19 among which the upregulated metalloprotease ADAM9 was key. This gene signature was supported in a second independent cohort of 81 critical and 73 recovered COVID-19 patients, as were ADAM9 transcripts, soluble form and proteolytic activity. Ex vivo ADAM9 inhibition affected SARS-CoV-2 uptake and replication in human lung epithelial cells. In conclusion, within a young, otherwise healthy, COVID-19 cohort, we provide the landscape of biological perturbations in vivo where a unique gene signature differentiated critical from non-critical patients. The key driver, ADAM9, interfered with SARS-CoV-2 biology. A repositioning strategy for anti-ADAM9 therapeutic is feasible.

We report six cases of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, admitted to intensive care unit (ICU), for whom bone marrow aspirate revealed hemophagocytosis. We compared their clinical presentation and laboratory findings to those that can be encountered during a hemophagocytic lymphohistiocytosis. These observations might evoke a macrophage activation mechanism different from the one encountered in the hemophagocytic lymphohistiocytosis (HLH).

CD9 plays a crucial role in cellular growth, mobility, and signal transduction, as well as in hematological malignancy. In myeloid neoplasms, CD9 is involved in the altered interactions between leukemic and stromal cells. However, apart from its role in CD34+ progenitors and myeloid and megakaryocytic differentiation, its function in normal and leukemic pluripotent cells has not yet been determined. Very small embryonic-like stem cells (VSELs) are promising pluripotent stem cells found in adult tissues that can be developed for safe and efficient regenerative medicine. VSELs express different surface receptors of the highest importance in cell functioning, including CD9, and can be effectively mobilized after organ injury or in leukemic patients. In the present study, we observed that CD9 is among the most expressed receptors in VSELs under steady-state conditions, however, once the VSELs are expanded, CD9+ VSELs decrease and are more apoptotic. CD9– VSELs had no proliferative improvement in vitro compared to those that were CD9+. Interestingly, the addition of SDF-1 induced CD9 expression on the surface of VSELs, as observed by flow cytometry, and improved their migration. In addition, we observed, in the phenotypically identical VSELs present in the peripheral blood of patients with myeloproliferative neoplasms, compared to healthy subjects, a significantly higher number of CD9+ cells. However, in their hematopoietic stem cell (HSC) counterparts, the expression remained comparable. These results indicate that, likewise, in progenitors and mature cells, CD9 may play an important function in normal and malignant VSELs. This could explain the refractoriness observed by some groups of expanded stem cells to repairing efficiently damaged tissue when used as a source in cell therapies. Understanding the function of the CD9 receptor in normal and malignant CD34+ and VSELs, along with its relationship with the CXCR4/SDF-1 pathway, will enable advances in the field of adult pluripotent cell usage in regenerative medicine and in their role in leukemia.

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic disorders frequently leading to severe anemia...

We have recently published in the Journal of Thrombosis and Haemostasis the presence of lupus anticoagulant (LAC) at high frequency in Covid‐19 patients (Harzallah et al.1). Bowles et al.2 and Helms et al.3 have confirmed these results in new publications. Tang4 has reported discordant data. He has found that very few tested covid‐19 patients had positive LAC in a small series (n=12). Bowles et al. have found that LAC were positive in 91% of patients (n=34) with high activated partial thromboplastin time (aPTT).

International audience; CD30 transmembrane receptor, a member of the tumor necrosis factor receptor family, is expressed in different lymphomas. Brentuximab vedotin (BV), a CD30 monoclonal antibody (Ab)-drug conjugate, is effective in CD30-positive lymphomas. However, the response to BV is not always correlated to CD30 expression detected by immunohistochemistry (IHC). The objectives of this study were to standardize and evaluate CD30 intensity by flow cytometry (FCM) in non-Hodgkin's lymphomas. Twelve centers analyzed 161 cases on standardized cytometers using normalized median fluorescence intensity (nMFI30) of three different Abs, of which one clone can recognize the same epitope as BV. FCM distinguished four groups of cases: negative group (n = 110) which showed no expression with the three clones; high positive group (n = 13) which gave nMFI30 > 5% with all tested clones; dim positive group (n = 17) which showed nMFI30 > 1% with all tested clones and

International audience; Background & aims - Ferroportin disease is a rare genetic iron overload disorder which may be underdiagnosed, with recent data suggesting it occurs at a higher prevalence than suspected. Costs and the lack of defined criteria to prompt genetic testing preclude large-scale molecular screening. Hence, we aimed to develop a readily available scoring system to promote and enhance ferroportin disease screening. Methods - Our derivation cohort included probands tested for ferroportin disease from 2008 to 2016 in our rare disease network. Data were prospectively recorded. Univariate and multivariate logistic regression were used to determine significant criteria, and odds ratios were used to build a weighted score. A cut-off value was defined using a ROC curve with a predefined aim of 90% sensitivity. An independent cohort was used for cross validation. Results - Our derivation cohort included 1,306 patients. Mean age was 55±14 years, ferritin 1,351±1,357 μg/L, and liver iron concentration (LIC) 166±77 μmol/g. Pathogenic variants (n = 32) were identified in 71 patients. In multivariate analysis: female sex, younger age, higher ferritin, higher LIC and the absence of hypertension or diabetes were significantly associated with the diagnosis of ferroportin disease (AUROC in whole derivation cohort 0.83 [0.78-0.88]). The weighted score was based on sex, age, the presence of hypertension or diabetes, ferritin level and LIC. An AUROC of 0.83 (0.77-0.88) was obtained in the derivation cohort without missing values. Using 9.5 as a cut-off, sensitivity was 93.6 (91.7-98.3) %, specificity 49.5 (45.5-53.6) %, positive likelihood ratio 1.8 (1.6-2.0) and negative likelihood ratio 0.17 (0.04-0.37). Conclusion - We describe a readily available score with simple criteria and good diagnostic performance that could be used to screen patients for ferroportin disease in routine clinical practice. Lay summary - Increased iron burden associated with metabolic syndrome is a very common condition. Ferroportin disease is a dominant genetic iron overload disorder whose prevalence is higher than initially thought. They can be difficult to distinguish from each other, but the limited availability of genetic testing and the lack of definitive guidelines prevent adequate screening. We herein describe a simple and definitive clinical score to help clinicians decide whether to perform genetic testing.

We have recently published in the Journal of Thrombosis and Haemostasis the presence of lupus anticoagulant (LAC) at high frequency in Covid‐19 patients (1). Different authors had confirmed these results (2). Connell and colleagues had discussed, in the Journal, technical points concerning LAC as well as anti‐phospholipids (aPL) auto‐antibodies detection (3).

In total, 279 patients with hairy-cell leukemia (HCL) were analyzed, with a median follow-up of 10 years. Data were collected up to June 2018. We analyzed responses to treatment, relapses, survival, and the occurrence of second malignancies during follow-up. The median age was 59 years. In total, 208 patients (75%) were treated with purine analogs (PNAs), either cladribine (159) or pentosatin (49), as the first-line therapy. After a median follow-up of 127 months, the median overall survival was 27 years, and the median relapse-free survival (RFS) was 11 years. The cumulative 10-year relapse incidence was 39%. In patients receiving second-line therapy, the median RFS was 7 years. For the second-line therapy, using the same or another PNA was equivalent. We identified 68 second malignancies in 59 patients: 49 solid cancers and 19 hematological malignancies. The 10-year cumulative incidences of cancers, solid tumors, and hematological malignancies were 15%, 11%, and 5.0%, respectively, and the standardized incidence ratios were 2.22, 1.81, and 6.67, respectively. In multivariate analysis, PNA was not a risk factor for second malignancies. HCL patients have a good long-term prognosis. PNAs are the first-line treatment. HCL patients require long-term follow-up because of their relatively increased risk of second malignancies.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for an ongoing global pandemic. Phase III trials have demonstrated excellent efficacies of mRNA vaccines against SARS-CoV-2 in large population studies (Baden LR, NEJM, 2021; Polack FP, NEJM, 2020). Immunosuppressed individuals such as chronic lymphocytic leukemia (CLL) patients are at risk for a suboptimal response to 2 vaccine doses (Herishanu Y, Blood, 2021). The French National Authority for Health recommends the use of a third dose in immunosuppressed patients. However, seroconversion rate after the triple-dose vaccine is not yet known. The objective of our study was to evaluate SARS-CoV-2 antibody responses after the first, second and third doses of the BNT162b2 and mRNA-1273 vaccines. Data were collected from 17 French Innovative Leukemia Organization (FILO) investigating centers and the French CLL patients' association (SILLC). SARS-CoV-2 IgG anti-Spike levels were measured at 4-6 weeks after each vaccine dose. A total of 530 patients and 14 controls were included in the study. Vaccine response was evaluated post-dose 1 for 158 CLL patients, post-dose 2, for 506 patients and post-dose 3 for 66 patients. Peripheral blood lymphocyte subsets were studied post-dose 2 by flow cytometry in 80 CLL patients and 14 controls. The median age of the patients was 71 years (range 37-93), 218 (40%) were treatment-naïve (TN), 136 (26%) had a prior CLL treatment and 176 (34%) were on therapy. Post-dose 1, the global response rate was 27% (43/158). TN patients had a response rate of 34% (23/67), similar to those who had a prior CLL treatment (33%,12/36), and higher compared to on-therapy patients (15%, 8/55, P=0.02). Post-dose 2, the global response rate was 52% (265/506). TN patients had the highest response rate of 72% (151/210) compared to previously treated patients, mostly by immunochemotherapy (60%, 78/130, P=0.02) and on-therapy patients (22%, 36/166, P65 years (OR 0.55, 95% CI 0.33-0.92, P=0.02), ongoing CLL treatment (OR 0.13, 95% CI 0.07-0.23, P Flow cytometry results suggest a differential balance of the T CD4+ cell subpopulations in Binet stage A and in patients on targeted therapy compared to healthy controls. Post-dose 2 seronegative patients were proposed a third dose and to date, 66 have been tested for the antibody response 4-6 weeks post-dose 3. The post-dose 3 response rate was 42% (28/66). TN patients and previously treated patients had a significantly higher response rate (57%, 16/28) compared to on-therapy patients (32%, 12/38, P=0.03). We further analyzed patients tested post-dose 2 with the Abbott Architect SARS-CoV-2 IgG anti-Spike assay (n=24). Those who achieved seroconversion after the third dose (n=10) had significantly higher titers post-dose 2 (median 12, IQR 3.0-40.8) compared to those who remained seronegative (n=14) (median 2.2, IQR 0.5-5.1, p An additional cohort of 40 CLL patients who presented a SARS-CoV-2 infection prior to vaccination participated to the study and was analyzed independently. All patients achieved seroconversion after infection and a single dose of vaccine, even though 30% (n=12) had an ongoing CLL treatment. In conclusion, double-dose mRNA vaccination generated a humoral response in 52% of our CLL cohort and a third dose induced seroconversion in 42% of the patients who remained seronegative after the second dose. The major independent predictor of negative antibody response was ongoing treatment with BTKi. The strongest boost to immune response against the virus seems to be SARS-CoV-2 infection, as a substantial increase in anti-Spike antibodies was observed in all CLL patients with prior infection, after a single dose vaccination. Figure 1 Figure 1. Disclosures Letestu: Janssen: Research Funding, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Research Funding, Speakers Bureau. Dartigeas: Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress. Laribi: Astellas Phama, Inc.: Other: Personal Fees; BeiGene: Other: Personal Fees; AstraZeneca: Other: Personal Fees; IQONE: Other: Personal Fees; AbbVie: Other: Personal Fees, Research Funding; Takeda: Other: Personal Fees, Research Funding; Novartis: Other: Personal Fees, Research Funding; Le Mans Hospital: Research Funding; Jansen: Research Funding. Cymbalista: Lilly-LOXO: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; ASTRA ZENECA: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: 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.

With the emergence of targeted therapies, defining the best strategy for the treatment of previously untreated CLL patients remains challenging. The aim of this phase 2 study was to compare the efficacy of an association with ibrutinib and venetoclax (IV) to the standard FCR regimen in fit patients with intermediate risk CLL defined by either unmutated IGHV status, 11q deletion or complex karyotype in the absence of TP53 abnormality. Patients were randomized 1:1 between two treatment arms, ie FCR 6 cycles or IV. After a lead-in phase of ibrutinib as a single agent from month (M)1 to M3, the total duration of treatment with IV was based on the response achieved at M9; if bone marrow (BM) MRD was < 0.01% using flow cytometry, the treatment was continued for 6 additional months until M15 and then stopped; if BM MRD at M9 was ≥ 0.01%, the treatment with IV was continued for 18 additional months until M27. The primary endpoint was the percentage of patients with BM MRD < 0.01% at M27 in both arms. We present here the preliminary results on the first evaluation done at M9 including CT-scan, BM biopsy and MRD assessment in PB and BM after the inclusion of all the 120 patients as initially planned. One hundred and twenty patients were enrolled from September 2019 to February 2021. The median age was 59 [34-72] and 61 [34-74] years in the FCR and IV arms, respectively. The characteristics of the patients were well balanced between the 2 arms in terms of gender (male 72% FCR, 74% IV), PS ECOG 0-1 (59% FCR, 68% IV) and Binet stage (A, B and C 15%, 64%, 21% for FCR ; 8.5%, 59% and 32% for IV). No major difference in terms of cytogenetic features was noted, all patients but one had unmutated IGHV. At the time of data cut-off for this interim analysis, the median follow-up for the all cohort was 11 [2.9 - 19.8] months. The frequency of all grades adverse events (AE) observed so far was 53% (grade 3-4, 24%) in the FCR arm and 47% (grade 3-4, 17%) in the IV arm. The rate of infusion-related reactions (IRR) in the FCR arm was 35% on cycle 1-day 1 (14% grade 3-4) ; for the IV arm, 6% of patients experienced tumor lysis syndrome (TLS) (grade 4 for 4 patients). ibrutinib doses were reduced for 7 patients (4 permanently stopped and 3 resumed at a lower dose because of toxicities (digestive, hepatic or haematological)). Venetoclax was permanently discontinued before M9 in 4 patients (digestive toxicities and grade 4 neutropenia). Forty serious adverse events were reported of which 15 in the IV arm (1 sudden death, 1 ischemic stroke, 2 atrial fibrillations, 2 clinical TLS, 1 hepatitis, 1 neutropenia, 4 COVID pneumonitis and one osteoporotic fracture) and 25 in the FCR arm (2 neutropenias, 1 anemia, 1 thrombocytopenia, 1 autoimmune haemolytic anemia, 3 IRR, 4 TLS, 2 COVID pneumonitis, 4 fever episodes of undetermined origin, 1 community-acquired pneumonia, 1 gastrointestinal toxicity, 1 confusion, 2 chest pains, 1 acute myeloid leukemia, 1 myelodysplasic syndrome). The patients with COVID pneumonitis had a favorable evolution with the need for intensive care and convalescent plasma for 3 of them. The first 60 patients included in the study have reached M9 and among them, 6 prematurely discontinued the study, 3 in each arm (active hemolysis, ischemic stroke and sudden death in the IV arm; 2 grade 4 hematologic toxicities and 1 early progression in the FCR arm). In the evaluated patients (n=54), 71% of patients in the FCR arm and 48% of patients in the IV arm achieved bone BM MRD < 0.01%. The complete (CR, CRi) and partial response rates were 54% and 46% in the FCR arm and 76% and 24% in the IV arm respectively. In conclusion, the preliminary results show a lower BM MRD rate in the IV arm compared to the FCR arm at M9, with a toxicity that remains significant and relatively similar between the two arms. However, BM MRD rate should improve after longer exposure to the IV combination and the analysis of the primary endpoint at M27 will be decisive in determining the best therapeutic strategy. Disclosures Quinquenel: Abbvie: Honoraria; Janssen: Honoraria; AstraZeneca: Honoraria. Laribi: Le Mans Hospital: Research Funding; Novartis: Other: Personal Fees, Research Funding; Takeda: Other: Personal Fees, Research Funding; BeiGene: Other: Personal Fees; IQONE: Other: Personal Fees; AbbVie: Other: Personal Fees, Research Funding; Astellas Phama, Inc.: Other: Personal Fees; AstraZeneca: Other: Personal Fees; Jansen: Research Funding. Cymbalista: Lilly-LOXO: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; ASTRA ZENECA: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: 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. Leblond: AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Lilly: Consultancy; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support; Roche: Honoraria; Amgen: Honoraria; Beigene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Dartigeas: Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel grants/Congress. Ferrant: Janssen: Other: Travel, Accommodations, Expenses; AbbVie: Honoraria, Other: Travel, Accommodations, Expenses; AstraZeneca: Honoraria. de Guibert: Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria. Feugier: Astrazeneca: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Honoraria; Janssen: Consultancy, Honoraria. Cartron: Roche, Celgene-BMS: Consultancy; Danofi, Gilead, Novartis, Jansen, Roche, Celgene-BMS, Abbvie, Takeda: Honoraria. Ysebaert: Abbvie, AstraZeneca, Janssen, Roche: Other: Advisory Board, Research Funding.

Background Richter syndrome (RS) refers to the onset of aggressive lymphoma, mostly diffuse large B cell lymphoma (DLBCL), in patients with chronic lymphocytic leukemia (CLL). The outcome of RS patients is usually very poor with both low response rates to chemoimmunotherapy and short survival. While BCR and BCL2 inhibitors have transformed the management of CLL patients, these drugs do not prevent the onset of RS. Modulating anti-tumor immunity has recently been suggested as a promising approach in RS (Ding, 2017). Blinatumomab is a bi-specific T-cell engaging antibody construct that transiently links CD3-positive T cells to CD19-positive B-cells, inducing T-cell activation and subsequent lysis of tumor cells. It has been approved for the treatment of patients with relapsed or refractory B-ALL and has also been evaluated in the setting of persisting minimal residual disease. Recently, blinatumomab (stepwise dosing 9-28-112 μg/d) has been evaluated in patients with relapsed or refractory DLBCL and demonstrated promising results (ORR 43%) with acceptable safety (Viardot, 2016). We hypothesized that blinatumomab would improve response in RS patients failing to achieve CR after initial debulking with R-CHOP. Methods We report here the first results of a phase 2 multicenter study investigating the efficacy and safety of blinatumomab after R-CHOP debulking therapy for patients with untreated RS of DLBCL histology (NCT03931642). The patients with persisting (PR, SD) or progressive disease (PD) after 2 cycles of R-CHOP were eligible to receive an 8-week course of blinatumomab induction. Blinatumomab was administered at a stepwise dose of 9 μg/d in the first week, 28 μg/d in the second week, and 112 μg/d thereafter. The primary endpoint was CR rate according to the revised Lugano criteria after the 8-week induction course of blinatumomab. An additional 4-week consolidation cycle was optional. Allo-HSCT was further allowed for eligible patients. Results A total of 34 patients out of 41 has already been enrolled in the trial to date. Median age was 66 years (range, 38-82) and sex ratio M/F was 23/12. CLL features at baseline were as follows: 57% had 17p deletion and 67% TP53 mutations. Sixty-five percent had complex karyotype and 79% unmutated IGHV status. Median number of prior therapeutic lines for CLL was 2 (range, 0-7): 19 (54%) patients previously received chemo-immunotherapy, 23 (66%) patients were exposed to ibrutinib and 11 (31%) to venetoclax. As of the data cut-off of June 1st, 2021, the blinatumomab induction course has been completed for 18 patients. Ten patients did not receive blinatumomab for the following reasons: 7 patients achieved CR after R-CHOP, 2 patients died because of febrile neutropenia after R-CHOP and 1 patient presented severe pneumonia after R-CHOP. Three patients are still on R-CHOP and 3 others on blinatumomab to date. Regarding toxicity during blinatumomab, data are available for the 18 patients having completed the blinatumomab induction to date. All patients had at least one grade 1 adverse event (AE), 10 had grade ≥3 AE. The most common AE (> 1 case), regardless of relationship to blinatumomab, were fever (4 patients), CRS (2 patients), sepsis (2 patients), vein thrombosis (2 patients), anemia (4 patients), neutropenia (3 patients), lymphopenia (5 patients), thrombocytopenia (3 patients) and hyperglycemia (5 patients). In terms of neurologic events, 5 (28%) experienced neurotoxicity (all recovered) including grade 3 encephalopathy, grade 4 confusion, grade 3 anxiety, grade 1 myoclonus, grade 2 ataxia, grade 1 sleep disorder and grade 1 ICANS (each in 1 pt). Blinatumomab was temporarly stopped in 3 patients and permanently in 2. In terms of efficacy, after R-CHOP debulking therapy (n=31 evaluable patients), 7 patients achieved CR, 6 patients were in PR, 7 patients were stable and 11 patients were progressive. At evaluation after the blinatumomab induction (n=18 evaluable patients), 4 (22.2%) patients achieved CR, 4 (22.2%) patients PR, 2 (11.1%) patients were stable and the remaining 8 (44.5%) were progressive. Considering the whole strategy (including R-CHOP debulking) (n=28), 15 (54%) patients achieved overall response including 11 (39%) CR. Conclusions Our preliminary data suggest that blinatumomab suggests encouraging anti-tumor activity and acceptable toxicity in patients with RS. Disclosures Ysebaert: Abbvie, AstraZeneca, Janssen, Roche: Other: Advisory Board, Research Funding. Ferrant: AstraZeneca: Honoraria; Janssen: Other: Travel, Accommodations, Expenses; AbbVie: Honoraria, Other: Travel, Accommodations, Expenses. de Guibert: Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria. Laribi: Astellas Phama, Inc.: Other: Personal Fees; AstraZeneca: Other: Personal Fees; Novartis: Other: Personal Fees, Research Funding; Le Mans Hospital: Research Funding; IQONE: Other: Personal Fees; Jansen: Research Funding; BeiGene: Other: Personal Fees; Takeda: Other: Personal Fees, Research Funding; AbbVie: Other: Personal Fees, Research Funding. Feugier: Abbvie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Amgen: Honoraria; Astrazeneca: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. OffLabel Disclosure: blinatumomab is approved for acute lymphoblastic leukemia. The aim of this phase 2 study is to evaluated it in patients with Richter's syndrome.

Background Peripheral T-cell lymphoma (PTCL) is a heterogeneous and accounts for approximately 10% of all lymphomas. Outcome of relapse/refractory (R/R) PTCL is poor with median progression-free survival (PFS) and overall survival (OS) of 3 and 6 months in the absence of stem-cell transplantation (SCT). [Mak, JCO, 2013]. Brentuximab vedotin (BV) monotherapy is approved for R/R systemic anaplastic large cell-lymphoma (ALCL) based on 86% overall response rate (ORR) and 57% complete remission (CR). [Pro, JCO, 2012]. In other CD30-positive (CD30+) R/R PTCL, the ORR of BV is 41%. Gemcitabine (G) used as monotherapy in control arm in the randomized phase 3 LUMIERE trial, provided ORR and CR rates of 35 and 22% respectively. [O'Connor, JCO, 2019]. Considering these results we designed a phase 2 study for R/R CD30+ PTCL combining G and BV with the primary end point to increase the ORR by 15%, compared to G monotherapy. Patients (pts) and Methods: Pts with histologically confirmed CD30+ (≥5%) PTCL who failed or were refractory to 1-3 prior lines of systemic therapy, with measurable disease and ECOG performance status < 3 were eligible. Pts received an induction of 4 cycles of G-BV (28-days cycles; G: 1000 mg/m² at D1 and D15 plus BV: 1.8 mg/kg at D8). Pts with CR or partial remission (PR) and non-eligible for SCT, received BV maintenance 1.8 mg/kg at D1 (21-days cycles) up to 12 cycles. The primary endpoint was the ORR (CR + PR) according to Lugano criteria based on CT-scan. Secondary objectives included tolerance and safety, DOR, PFS, OS and impact of BV maintenance. Eligible pts were censored at time of SCT. (NCT03496779). Results: From April 2018 to October 2019, 71 pts were included. Pathology central review according to WHO 2017 criteria, so far available for 50 patients, confirmed angioimmunoblastic T-cell lymphoma (AITL) (22 ; 31%); nodal PTCL-TFH (5 ; 7%); PTCL-NOS (5 ; 7%); ALK- ALCL (10 ; 14.1%) ; ALK+ ALCL (4 ; 5.6%), Enteropathy associated T-cell lymphoma (EATL) (2 ; 2.8%); unclassified PTCL (2 ; 2.8%). There were 47 male and 24 female with a median age of 66 years (20-79) and 17 pts were > 75 years. Median time from diagnosis to enrolment was 9.4 months (range, 6-21). Sixty-five pts (91.6%) presented with stage III-IV. The number of prior lines of therapy were 1 (57 pts), 2 (11 pts) or 3 (3 pts), all pts had received previous CHOP-like chemotherapy, 11 pts previous autologous SCT, 5 pts epigenetic modifiers and 39.4% were refractory to their last line of treatment prior to inclusion. The cut-off date of this analysis was 01/31/2020. The 4 cycles of G-BV induction were completed in 45 pts (63%). The reasons for early discontinuation were progression (21 pts), death (3 pts) or adverse event (2 pts). In intention-to-treat analysis, the ORR at the end of induction (EOI) was 47.9% including CR (14 pts; 19.7%), PR (20 pts; 28.2%). PET performed in all patients reaching EOI showed overall and complete metabolic responses in 45.1 and 23.9%, respectively. During G-BV induction 58 pts (81.7%) had at least one G > 3 adverse event (AE) including neutropenia (67.2%), thrombopenia (17.2%), infections (15.5%), peripheral neuropathy (PN) (5.2%) and cardiac event (5.2%). Overall PN of any grade was recorded in 8/71 patients (11%) during G-BV induction and caused BV withdrawal in one case. Among the 34 responding pts after EOI, 27 pts began BV maintenance and 7 pts remain on maintenance at cut-off date. Eight pts were removed from the study due to SCT eligibility, either after the 4 GBV induction (4 pts) or after 1 or 2 maintenance BV cycles (4 pts). With a median follow-up (FU) of 9.5 (0.5-19.4) months, median PFS is 4.5 months (95%CI [3.5 - 10]) and median OS is 12 months (95%CI [8.6 - NR]). Among the 34 patients in PR/CR after induction, the duration of response (DOR) is 12.8 months (95%CI [10.3 - NR]). At last FU were recorded 32 deaths. Disease status at time of death was PD (25 pts), CR (1 pt) NE or missing (6 pts). Conclusion: The addition of BV to G increases the overall response rate by 15% in the treatment of R/R CD30+ PTCL. OS data are encouraging for this overall R/R patient population but PFS is overall short and a longer FU is mandatory. Especially the DOR of pts achieving CR or PR after 4 cycles of G-BV exceeds 1 year on BV maintenance. This combination is generally well tolerated and this study suggests that G-BV combination could be an interesting alternative for R/R CD30+ PTCL. Disclosures Tournilhac: Janssen: Consultancy, Honoraria, Other: Travel grant; INNATE Pharma: Consultancy, Honoraria; GILEAD: Consultancy, Honoraria, Other: Travel Grant; ABBVIE: Consultancy, Honoraria, Other: Travle grant; Takeda: Consultancy, Honoraria, Other: Travel grant. Laribi:novartis: Honoraria, Research Funding; amgen: Research Funding; abbvie: Honoraria, Research Funding; takeda: Research Funding. Ysebaert:AbbVie: Consultancy; Roche: Consultancy; Janssen: Consultancy. Guidez:BMS: Honoraria; TAKEDA: Honoraria; Service Hématologie et Thérapie cellulaire CHU POITIERS: Current Employment; AMGEN: Honoraria; CELGENE: Honoraria; JANSEN: Honoraria. Le Gouill:Loxo Oncology at Lilly: Consultancy; Roche Genentech, Janssen-Cilag and Abbvie, Celgene, Jazz pharmaceutical, Gilead-kite, Loxo, Daiichi-Sankyo and Servier: Honoraria. André:Celgene: Other, Research Funding; Takeda: Consultancy; Bristol-Myers-Squibb: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Karyopharm: Consultancy; Gilead: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Novartis: Consultancy, Research Funding; Amgen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Johnson & Johnson: Research Funding; CHU UCL Namur, site Godinne, Yvoir, Belgium: Current Employment; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Abbvie: Consultancy; Seattle Genetics: Consultancy. Dupuis:Henri Mondor University Hospital Creteil France: Current Employment. Thieblemont:Roche, Amgen, Kyte Gilead, Celgene, Abbvie, Novartis, Cellectis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche, Hospita: Research Funding; Cellectis: Speakers Bureau. Bachy:Beigene: Membership on an entity's Board of Directors or advisory committees; Roche, Gilead: Consultancy; Amgen: Research Funding; Roche, Celgene, Amgen, Janssen, Gilead, Novartis, Sanofi: Honoraria. Morschhauser:Celgene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; F. Hoffmann-La Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Epizyme: Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy; Servier: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Feugier:janssen: Consultancy, Honoraria, Research Funding; gilead: Consultancy, Honoraria, Research Funding; roche: Consultancy, Honoraria, Research Funding; astrazeneca: Consultancy, Honoraria, Research Funding; abbvie: Consultancy, Honoraria, Research Funding. Cartron:F. Hoffmann-La Roche: Consultancy, Honoraria; Abbvie: Honoraria; Jansen: Honoraria; Celgene: Consultancy, Honoraria; Sanofi: Honoraria; Gilead: Honoraria. Camus:ROCHE: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); JANSSEN: Honoraria; AMGEN: Honoraria; PFIZER: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Sibon:takeda france: Consultancy. Snauwaert:roche: Other: travel; janssen: Other: travel; abbvie: Other. Delarue:BMS: Other: stock options ; Celgene/BMS: Current Employment. De Leval:Abbvie: Honoraria; Lausanne University Hospital & Lausanne University Institute of Pathology: Current Employment; Roche Diagnostics: Honoraria; Lunaphore Technologies SA: Consultancy, Honoraria. Gaulard:CHU Henri Mondor, Assistance Publique-Hôpitaux de Paris: Current Employment; TAKEDA: Consultancy, Honoraria, Research Funding; INNATE PHARMA: Research Funding; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company).

Neoplasms involving plasmacytoid dendritic cells (pDC) include blastic pDC neoplasms (BPDCN) and other pDC proliferations, where pDC are associated with myeloid malignancies: most frequently chronic myelomonocytic leukemia (CMML) but also acute myeloid leukemia (AML), hereafter named pDC-AML. We aimed to determine the reactive or neoplastic origin of pDC in pDC-AML, and their link with the CD34+ blasts, monocytes or conventional DC (cDC) associated in the same sample, by phenotypic and molecular analyses (targeted next-generation sequencing, 70 genes). We compared 15 pDCAML at diagnosis with 21 BPDCN and 11 normal pDC from healthy donors. CD45low CD34+ blasts were found in all cases (10-80% of medullar cells), associated with pDC (4-36%), monocytes in 14 cases (1-10%) and cDC (two cases, 4.8-19%). pDC in pDC-AML harbor a clearly different phenotype from BPDCN: CD4+ CD56– in 100% of cases, most frequently CD303+, CD304+ and CD34+; lower expression of cTCL1 and CD123 with isolated lymphoid markers (CD22/CD7/CD5) in some cases, suggesting a prepDC stage. In all cases, pDC, monocytes and cDC are neoplastic since they harbor the same mutations as CD34+ blasts. RUNX1 is the most commonly mutated gene: detected in all AML with minimal differentiation (M0-AML) but not in the other cases. Despite the low number of cases, the systematic association between M0-AML, RUNX1 mutations and an excess of pDC is puzzling. Further evaluation in a larger cohort is required to confirm RUNX1 mutations in pDC-AML with minimal differentiation and to investigate whether it represents a proliferation of blasts with macrophage and DC progenitor potential.

International audience; Background & aims - We have reported a significant association between HLA-G expression or the number of hepatic mast cells and liver fibrosis. Here, we investigated the role of HLA-G and mast cells in liver fibrosis, focusing, in particular, on interactions between human mast and stellate cells. Methods - Human mast cells (HMC cell line, CD34-derived mast cells, or tissue-derived mast cells) were co-cultured with purified human hepatic stellate cells (HSCs), and collagen I production by HSCs was evaluated. Mast cells and HSCs were characterized by immunocytochemistry. Various conditions were tested: different times in direct or indirect contact, presence or absence of cytokines, addition or not of HLA-G, and presence or absence of specific protease inhibitors. Results - The reciprocal interaction between HSCs and mast cells led to the attraction of mast cells to HSCs in vivo and in vitro, and to a significant decrease in collagen production, at all times of co-culture, following the direct or indirect contact of mast cells with HSCs alone or in the presence of TGF-β, IFN-α or IL-10. We identified the diffusible factors involved in collagen I degradation as mast cell proteases. Moreover, HLA-G expression increased during the co-culture of HSCs and mast cells, with HLA-G acting on both mast cells and HSCs, to enhance collagen I degradation. Conclusions - Mast cells play a beneficial, anti-fibrotic role in liver fibrosis, via the HLA-G-mediated decrease of collagen I. These findings are consistent with high levels of cross-communication between mast cells and hepatic stellate cells and the role of HLA-G.

Background Central nervous system lymphomas are aggressive tumors requiring a prompt diagnosis for successful treatment. Stereotactic biopsy remains the standard procedure, but the time needed for histopathology is usually over 2 days. We evaluated the contribution of cytomorphology and flow cytometry to histopathology of the brain biopsy in particular on the rinse fluid usually removed. Methods Eighteen patients with suspected localized brain lymphoma underwent stereotactic brain biopsy. Brain biopsy tissue sample and/or brain biopsy rinse fluid were analyzed by cytomorphology combined with flow cytometry. Histopathology was used as a reference. Results Histopathology characterized ten diffuse large B-cell lymphomas and eight other diseases. Cytomorphology and flow cytometry showed lymphoma cells in nine out of the ten lymphomas. Three cytomorphology or flow cytometry negative results were reported for lymphomas in tissue samples due to low cellularity and biopsy sample conditioning. No lymphomatous cells were found by cytomorphology or flow cytometry in the eight other diseases. Rinse fluid results were consistent with histology in all cases studied (sensitivity and specificity, 100%). The median time to result was 4.5 days (range, 2-10 days) for histopathology, while 5 h (range, 3-20 h) were required for both cytomorphology and flow cytometry. Conclusions Brain biopsy rinse fluid alleviates problems of tissue sample distribution compared to tissue sample. Its analysis performs the diagnosis of B-cell lymphoma in a few hours and, associated with histopathology, allows a multidisciplinary diagnosis. This study shows that cytomorphology combined with flow cytometry on brain biopsy rinse fluid is a new, fast, and useful strategy. © 2016 International Clinical Cytometry Society.

Introduction Treatment of B-lineage lymphoma with B-cell depleting immunotherapy causes B-cell aplasia and impairs immune response. Case studies have reported patients treated with anti-CD20 therapy who suffered from persistent Covid-19. We aimed to assess the incidence, risk factors and long-term outcomes of persistent Covid-19 in patients with lymphoma. Patients and methods This retrospective multicentric study was conducted in 16 French hospitals. All adult patients with lymphoma who were admitted for Covid-19 in March and April 2020 were included. Persistent Covid-19 was defined as persisting severe Covid-19 symptoms requiring in-hospital stay for >30 days. Patients who re-experienced severe Covid-19 symptoms after initial improvement, requiring repeated hospitalizations for a total in-hospital length of stay >30 days were added to the persistent Covid-19 cases. Results One hundred eleven patients were included. Thirty days after admission for Covid-19, 24 patients had died, 55 had been definitively discharged from hospital, 31 were still hospitalized and 1 was later rehospitalized for Covid-19 recurrence. The incidence of persistent Covid-19 was 32/111 (29%). Patients with persistent Covid-19 had a median age of 64 years (range, 43-87) and 63% were male. Twenty-two patients (69%) had at least one significant comorbidity. None of the patients with T-cell (n=8) lymphoma or classical Hodgkin’s disease (n=8) experienced persistent Covid-19. In the 32 patients with persistent Covid-19, the median time between first admission and final discharge was 58 days (range, 31-235) and the median duration of Covid-19 symptoms was 83 days (range, 32-237). Eight patients received corticosteroids and 9 convalescent plasma: all patients recovered from their symptoms, except one. Overall, 9 patients with persistent Covid-19 died (27%). After a median follow-up of 191 days (range, 3-260), the 6-month overall survival was 69% (95% CI 60-78%) for the whole cohort. In multivariate analysis, administration of anti-CD20 monoclonal antibody within 12 months before admission to hospital for Covid-19 was both associated with decreased overall survival (HR 2.13, 95% CI 1.03-4.44, p = 0.043) and prolonged in-hospital stay (HR 1.97, 95% CI 1.24-3.13, p = 0.004). The two other significant factors associated with decreased overall survival and prolonged in-hospital stay: age ≥ 70 years and refractory or relapsed lymphoma. Conclusion Patients with B-cell non-Hodgkin lymphoma hospitalized for Covid-19 have a high incidence of prolonged evolution of SARS-CoV-2 infection. Administration of anti-CD20 therapy within the last 12 months is one of the main risk factors for longer in-hospital stay and death of Covid-19. The risk of persistent Covid-19 was also higher in patients older than 70 years or with refractory or relapsed disease. These findings may contribute to guide the management of lymphoma patients during the Covid-19 pandemic. Citation Format: Sylvain Lamure, Remy Dulery, Marc Delord, Roberta Di Blasi, Adrien Chauchet, Thomas Hueso, Cédric Rossi, Bernard Drenou, Bénédicte Deau-Fischer, Carole Soussain, Pierre Feugier, Nicolas Noel, Sylvain Choquet, Serge Bologna, Bertrand Joly, Laure Philippe, Milena Kohn, Sandra Malak, Guillemette Fouquet, Etienne Daguindau, Sophie Bernard, Yassine Taoufik, Karine Lacombe, Guillaume Cartron, Catherine Thieblemont. High incidence of persistent COVID-19 among patients with lymphoma treated with B-cell depleting immunotherapy [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2021 Feb 3-5. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(6_Suppl):Abstract nr S09-02.

International audience; Erythropoiesis-stimulating agents are generally the first line of treatment of anemia in patients with lower-risk myelodysplastic syndrome. We prospectively investigated the predictive value of somatic mutations, and biomarkers of ineffective erythropoiesis including the flow cytometry RED score, serum growth-differentiation factor-15, and hepcidin levels. Inclusion criteria were no prior treatment with erythropoiesis-stimulating agents, low- or intermediate-1-risk myelodysplastic syndrome according to the International Prognostic Scoring System, and a hemoglobin level 4 (P=0.05) and a hepcidin:ferritin ratio 2000 pg/mL and a hepcidin:ferritin ratio

Background Eltrombopag (ELT), an oral thrombopoetin-receptor agonist, has recently emerged as an encouraging and promising agent in acquired aplastic anemia. It has shown efficacy within clinical trials exploring its role in the first - line therapy in addition to standard immunosuppressive therapy as well as in the refractory setting (Townsley et al, NEJM 2017; Olnes et al, NEJM 2012). How ELT is used outside of clinical trials in the real-world setting after approval in Europe and results of this treatment are not known. Methods We conducted a retrospective survey on the use of thrombopoietin agonists for AA among EBMT member centers. Thirty-one centers provided data on 137 patients treated between 11/2011 to 10/2017. We merged our dataset with the cohort from the French Reference Center for Aplastic Anemia (Lengline et al., Haematologica 2017). Here we report the outcome 165 patients having received at least 30 days ELT and having a follow up of at least 2 months, patients with a shorter duration of treatment or follow up, as well as three patients receiving romiplostim were excluded. The following response criteria were used: complete response (CR) defined as hemoglobin >100g/l, neutrophil count >1.5 x106/ml and platelet count >100 x106/ml; partial response (PR) corresponding to transfusion independence and minimal response (MR) to some improvement in one or more lineage but not fulfilling the criteria of PR. Results The median follow-up was 14 months (IQR 7-24 months). Before starting ELT, AA was classified as severe or very severe in 68.6% respectively 13.8 % of patients. At last follow-up 87.3% of patients were alive, of those 47.2% continued ELT (maximum median dose: 150mg/day). A minority of the patients (n=22, 13.3 %) received ELT upfront, i.e. within 60 days following initiation of first-line treatment, whereas most patients were treated with ELT as a rescue treatment either for insufficient response to previous treatment(s) (n= 122, 73.9%) or relapse (n=21, 12.7%). ELT was applied both as monotherapy (n= 56, 33.9%) and in combination with IS (ELT+ CYA: n= 87/52.7%, ELT+CYA/ATG: n=20/12.1% , Fig. 1 a). Importantly, 69.7% of patients received ELT outside the FDA/EMA label, either in the first line setting or as part of a combination therapy. The reported overall response rate in our cohort was 64.6 %, with 19.5 % CR, 28% PR and 17.1% minimal response. Best response was achieved in median after 252 days (95% CI 181-366 days). In univariate models, we could not identify any baseline characteristics associated with better response in the whole cohort, although severity of AA before start of ELT was significantly associated with death without a response (p= 0.024). In the multivariate model, combination therapy was a predictor (p=0.049) of response, with a hazard ratio for response of 3.32 for the ELT/CYA/ATG group compared to ELT monotherapy (p=0.008). In the subgroup of patients with previous therapy, response to previous therapy was a strong predictor of response (HR 2.2, p The median survival was not reached in our cohort, the 1-year survival from start of ELT was 87.9%. Twenty-one (12.7 %) patients died during follow-up, seven (33%) of these had undergone allo-HSCT and in six (28.6%) deaths were classified as HSCT-related. In univariate and multivariate analysis, AA severity at ELT start and response to ELT were associated with OS. Interestingly, the better survival of patients responding to ELT was driven by CR and PR, as patients with a minimal response to ELT had the same survival as patients without a response (Fig 1b.). Adverse events (AEs) were reported in 30.6% of patients, although severe (grade III-IV) AEs were rare (8.9%) and ELT was stopped only in 2 patients due to AEs. Cytogenetic abnormalities were assessed systematically only at diagnosis and showed a normal karyotype in 70.9% of patients and an abnormal karyotype in 11 cases (7.9%) including 3 cases of trisomy 8 and 1 case of inv(3;3q26). Only 2 cases of MDS diagnosed 2 and 5.5 months after ELT start were reported. Conclusions ELT is used widely in Europe to treat AA patients, mostly in the relapsed/refractory setting. Whereas patients achieving at least transfusion independence with ELT have an excellent survival, the outcome of patients refractory to ELT remain unsatisfactory. Disclosures Cortelezzi: janssen: Consultancy; abbvie: Consultancy; novartis: Consultancy; roche: Consultancy. Gaidano:Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Morphosys: Honoraria; Gilead: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Peffault De Latour:Pfizer Inc.: Consultancy, Honoraria, Research Funding; Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen Inc.: Research Funding.

Few therapeutic options are available for patients with aplastic anemia who are ineligible for transplantation or refractory to immunosuppressive therapy. Eltrombopag was recently shown to produce trilineage responses in refractory patients. However, the effects of real-life use of this drug remain unknown. This retrospective study (2012-2016) was conducted by the French Reference Center for Aplastic Anemia on patients with relapsed/refractory aplastic anemia, and patients ineligible for antithymocyte globulin or transplantation, who received eltrombopag for at least 2 months. Forty-six patients with aplastic anemia were given eltrombopag without prior antithymocyte globulin treatment (n=11) or after antithymocyte globulin administration (n=35) in a relapsed/refractory setting. Eltrombopag (median daily dose 150 mg) was introduced 17 months (range, 8-50) after the diagnosis of aplastic anemia. At last followup, 49% were still receiving treatment, 9% had stopped due to a robust response, 2% due to toxicity and 40% due to eltrombopag failure. Before eltrombopag treatment, all patients received regular transfusions. The overall rates of red blood cell and platelet transfusion independence were 7%, 33%, 46% and 46% at 1, 3, 6 months and last follow-up. Responses were slower to develop in antithymocyte treatment-naive patients. In patients achieving transfusion independence, hemoglobin concentration and platelet counts improved by 3 g/dL (interquartile range, 1.4-4.5) and 42×109/L (interquartile range, 11-100), respectively. Response in at least one lineage (according to National Institutes of Health criteria) was observed in 64% of antithymocyte treatment-naive and 74% of relapsed/refractory patients, while trilineage improvement was observed in 27% and 34%, respectively. We found high rates of hematologic improvement and transfusion independence in refractory aplastic anemia patients but also in patients ineligible for antithymocyte globulin receiving first-line treatment. In conclusion, elderly patients unfit for antithymocyte globulin therapy may benefit from eltrombopag.

INTRODUCTION: Erythropoiesis stimulating agents (ESA) are generally the first line of treatment of anaemia in lower risk myelodysplastic syndrome (MDS) patients. We prospectively investigated the predictive value of somatic mutations, and biomarkers of ineffective erythropoiesis including flow cytometry RED score, serum GDF-15, and hepcidin levels. METHODS: Inclusion criteria were: ESA naive, IPSS low or intermediate-1 MDS with Hemoglobin (Hb) level< 10g/dL. Patients received epoetin zeta 40 000 IU/week and erythroid response (HI-E, IWG 2006 criteria) was assessed at W12. sEPO level, iron parameters and hepcidin, flow cytometry (FC) Ogata and Red Score (RS), GDF-15, and molecular analysis by NGS were determined at baseline. RESULTS: 70 patients were included. Median age was 78 years. There were 22 RCMD, 19 RCUD, 14 RARS, 4 RAEB-1, 6 CMML, 2 del 5q-, 3 unclassifiable, R-IPSS was 13 very low, 47 low, 9 intermediate and high. Twenty patients were transfusion-dependent. HI-E was 48% and median duration of response was 26 months. At baseline, non-responders had significantly higher FC Red Score, lower hepcidin/ferritin ratio, lower IPSS. In multivariate analysis, only RS>4 at T0 (p=0.05) and hepcidin/ferritin 2000 pg/ml and hepcidin/ferritin

Introduction: Since the publication of the International Guidelines (Borowitz, 2010; Illingworth, 2018), no study has assessed the long-term evolution of paroxysmal nocturnal hemoglobinuria (PNH) clones using high-resolution flow cytometry. The sole evaluation, performed by Sugimori et al, using a 2-color flow cytometry test, showed the disappearance of PNH clones in 24% of patients with bone marrow (BM) failure over 5 years (Sugimori, 2009). A diagnostic practice harmonization using high-resolution flow cytometry has spread in France since 2013 through an on-going inter-laboratory comparison program (Debliquis, 2015). Thus, our HPNAFC group has been able to initiate a French nation-wide multicenter prospective observational study. Objective: We aimed to assess the evolution of PNH clones over a long term period using mostly high sensitivity test, which is required for minor clone assessment, with validated flow cytometry data. Methods: All patients of any age with a PNH clone or GPI-deficient cells ≥0.01%, newly- or previously-diagnosed, detected in France from February 29th 2016, could be included in this Observatory, provided that the center had validated a PNH flow cytometry quality control. For each patient, the baseline assessment was always considered as the initial PNH clone detection, even if it occurred before the initiation of the Observatory. Thus, this strategy allowed the collection of cases with long-term follow-up. Referent cytometrist of each center included patients in the e-CRF available on the HPNAFC website providing clinical and biological information as well as flow cytometry raw data files. This study was approved by the national research ethics board. Results: As of July 15th 2019, 48 participating flow cytometry laboratories across France have enrolled 356 patients with a PNH clone or GPI-deficient cells ≥ 0.01%. All cases have been carefully reviewed by the 2 principal investigators, who both thoroughly re-examined flow cytometry data and the e-CRF filling that led to the update of roughly one third of the submitted files. This enabled the validation of 200 patients at diagnosis, the remaining 156 being ongoing. One hundred and three of the 200 validated patients displayed at least one follow-up point (more than 3 months apart from the diagnosis) with a clone size determined at diagnosis (see flow chart figure 1A). For 8/103 patients, exchanges with centers are still ongoing. Thus, we were able to assess the evolution of PNH clones of 95 patients with 2 [range: 1-8] follow-up points over a period of 4.1 [0.3-14.2] years, corresponding to 200 validated follow-up points. The patient median age at diagnosis was 40 years old [10-85] with 3 pediatric cases ( Conclusion: This multicenter study based on robust flow cytometry analysis showed no disappearance of PNH clones, including minor ones, over a long period of time, regardless of the clinical manifestations, except for patients who underwent BM transplantation. Moreover, PNH clone size increased in half of patients with BM failure, justifying a long term PNH clone size monitoring, even in these patients. Figure 1 Disclosures Le Garff-Tavernier: Alexion: Consultancy, Honoraria. Pruvot Debliquis:Alexion: Honoraria; Takeda: Honoraria; Pfizer: Honoraria; Gilead: Honoraria; Genzyme: Honoraria. Socie:Alexion: Consultancy. Peffault de Latour:Alexion: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Research Funding. Drenou:Alexion: Consultancy, Honoraria. Wagner Ballon:Alexion: Consultancy, Honoraria.

Introduction: Hairy-cell leukemia (HCL) is a chronic B-cell lymphoproliferative disorder with a favorable outcome thanks to treatment with purine analogues (PNA) like cladribine and pentostatin. Here, we updated the French national retrospective cohort of HCL after 10 years of follow-up, in order to evaluate the risk of second cancers in these patients. Methods: Data were collected up to June 2018 through a questionnaire sent to the members of the Société Française d'Hématologie, and centralized in the cohort database. We described the second malignancies observed during the follow-up, distinguishing second 'solid' cancers from second hematological malignancies. Then, using a Fine and Gray model, we performed a multivariate analysis in order to identify second cancer risk factors. Finally, to evaluate the excess of cancers in our cohort in comparison with the French general population, we calculated the standardized incidence ratio (SIR). Results: 279 patients (pts) from 19 centers were included in our retrospective cohort. The median age was 59 years old (range 29-88). 21% had an infectious disease at diagnosis, 23% had a familial history of cancer and 11% a personal history of cancer before HCL diagnosis. The median number of lines of treatments was 1 (0-7). PNA (cladribine or pentostatin) were the first therapeutic choice in frontline (75% of pts) and at relapse (69%). With a median follow-up of 127 months (2-413), the median overall survival for the overall study population was 328 months (95% CI 299-357) and the median relapse-free survival (RFS) was 136 months (95% CI 109-163). Pts treated with cladribine or pentostatin in first line had a statistically significant better RFS than pts treated with 'other' treatments (log rank test, p < 0.001). The 10-year cumulative incidence of relapse was 39% (95% CI 33-46). Pts who received treatments other than PNA in first line had a higher risk of relapse (Gray's test, p < 0.001). For pts receiving PNA in first and second lines, there was no difference in outcomes between those who switched PNA and those who did not. In this cohort, we observed 68 second malignancies during the follow-up: 49 solid cancers (most prevalent: prostate and non-melanoma skin cancers) and 19 hematological malignancies (most prevalent: monoclonal gammopathy of undetermined significance (MGUS) and myelodysplastic syndromes (MDS)). The median onset of second cancer, second solid cancer and second hematological malignancy from HCL diagnosis was 81 months, 99 months and 78 months, respectively. The median age at diagnosis of cancer, solid cancer and hematological malignancy was 70, 69 and 77 years old, respectively. Considering death as a competing risk, the 10-year cumulative incidence of cancer, solid cancer and hematological malignancy was 15% (95% CI 11-19), 11% (95% CI 7.2-15), and 5.0% (95% CI 2.8-8.2), respectively. In multivariate analyses, IFN treatment was associated with a decreased risk for all cancers (Fine and Gray regression model, subdistribution Hazard Ratio (sdHR) 0.53 (95% CI 0.29-0.97); p = 0.038), a familial history of cancer was a risk factor for solid cancers (sdHR 2.12 (95% CI 1.15-3.91); p = 0.017), a personal history of cancer was a risk factor for hematological malignancies (sdHR 3.47 (95% CI 1.14-10.55); p = 0.028). Even after excluding non-melanoma skin cancers and MGUS, there was an excess of cancers (SIR = 2.22), solid cancers (SIR = 1.81) and hematological malignancies (SIR = 6.67). Conclusions: In this updated real-world retrospective cohort with a long follow-up and most pts treated with PNA, we highlighted the importance and the excess of second cancers in HCL patients, in particular hematological malignancies. Figure Disclosures Paillassa: Janssen: Other: Bibliography board with young hematologists. Thieblemont:Roche: Honoraria, Research Funding; Gilead: Honoraria; Novartis: Honoraria; Kyte: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Cellectis: Membership on an entity's Board of Directors or advisory committees. Hermine:AB Science: Membership on an entity's Board of Directors or advisory committees. Feugier:janssen: Honoraria, Research Funding, Speakers Bureau; gilead: Honoraria, Research Funding, Speakers Bureau; roche: Honoraria, Research Funding, Speakers Bureau; abbvie: Honoraria, Research Funding, Speakers Bureau. Troussard:Innate Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: 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: Other: Research Support; Sysmex: Other: Research Support.

Flow cytometry (FC) instruments settings classically rely on local establishment of photomultipliers (PMT) voltages adapted to the measurements expected to be performed. In the era of multiparameter FC (MFC), it appears more and more desirable that comparable patterns of fluorescence are obtained in different settings. This relies on a harmonization of settings between instruments. Although this has been shown to be feasible within a given brand of flow cytometers, little information is available about broader comparisons in a given center or in a multicenter fashion. Here, we report a two-phase series of experiments first performed between a Canto II (BD Biosciences) and a Navios (Beckman Coulter) instruments in the same center. PMT values adjusted on the reference instrument (RI) Canto II were used to establish target values for PMT settings on the paired Navios practice instrument (PI). This allowed to show the good correlation of all but peaks 1 and 2 of Rainbow(®) beads between RI and PI. Using 4- or 8-color stained leukocytes, the similitude of the settings was further confirmed. A complex set of matrices was then established between five centers all equipped with both instruments. Using Bland & Altman difference comparisons for median fluorescence values, it was shown that using either Rainbow beads or CD16 stained polymorphonuclears to set-up target values on the RI CantoII, highly superimposable results could be obtained on all 9 PI. The latter were obtained using Rainbow beads or Compbeads(®) for comparisons. In summary, this two-phase study demonstrates the feasibility of different methods allowing for a robust harmonization of settings for MFC.

The IKZF1 gene encodes the Ikaros transcription factor, a key regulator of lymphocyte differentiation.1 IKZF1 is mutated in 20–30% of B-cell acute lymphoblastic leukemia (B-ALL) mostly by genomic deletions.2, 3, 4 Several reports have shown that IKZF1 deletions are associated with an adverse prognosis, especially in pediatric patients.3, 4, 5, 6, 7, 8, 9, 10 Ikaros mutations fall mainly into three types: (a) deletions of exons 4–7 (Δ4–7), which lead to the synthesis of the Ikaros-6 (Ik6) dominant-negative isoform; (b) deletions of exons 2–7 (Δ2–7), which delete the initiation codon and lead to haploinsufficiency; and (c) larger deletions of various sizes, which affect the coding exons (referred to below as ‘complete’ deletions). Thus, IKZF1 mutations have until now been separated into dominant-negative and haploinsufficient groups. Here we report that about 20% of B-ALL patients with IKZF1 mutations present two distinct deletions. These deletions are biallelic, leading to a complete loss of Ikaros function, or biclonal, marking distinct clones within the leukemia. These results highlight a more complex picture of IKZF1 loss of function in B-ALL than thought previously.

Introduction The CD30 antigen is expressed by a small number of cells in classical Hodgkin lymphoma (HL), by malignant cells in anaplastic large cell lymphoma (ALCL), and in several non-Hodgkin lymphomas (NHL). Brentuximab vedotin (BV), an anti-CD30 monoclonal antibody (Ab) conjugated to chemotherapy, showed its efficacy in HL and ALCL. However, a correlation between response to BV and CD30 expression in NHL is difficult to establish by immunohistochemistry (IHC) since the count of dimly positive cells is difficult to standardize. Flow cytometry (FCM) is a standardizable tool which allows the multiparametric characterization of malignant NHL cells and the quantification of proteins at the cell surface. The objective of this multicentric study is to standardize CD30 expression in NHL by quantitative FCM. Materiel and methods The nine centers used one or two cytometers: BD Biosciences (BD) n=7, Beckman Coulter (BC) n=4. The standardization was conducted using the Euroflow strategy, the same operating procedure and the same reagents. Abs recognizing different CD30 epitopes were: BerH83 (BD), HRS4 (BC) and a specific AC10 (Ancell) similar to BV. If tissue was available, pathologists locally used BerH2 (Dako) for IHC. The CD30 expression was normalized using Mean Fluorescence Intensity (MFI) to MFI CD4 expression and expressed as a percentage (nMFI30). Three cell lines (SUDHL4, K562 and L82) with differential expression of CD30 were shipped to the different laboratories in order to validate the centers using a robust statistical method. Then, NHL cases including anaplastic lymphomas, T lymphomas, and large B cell lymphomas were collected using a website www.mfi30.fr. All FCM Abs were used on available cells when nMFI30 >1% using Ancell Ab. Results On cell lines, all centers obtained similar results: z-scores between -2 to +2. Mean of nMFI30 were SUDHL4 0.1% (SD=0.1), K562 69.8% (SD=16.9), L82 292.9% (SD= 45.7) with BD Abs and 0.6% (SD=0.1), 229.9% (SD= 47.9) and 2053.8 (SD= 282) with BC Abs , respectively, demonstrating that BD and BC Abs are not equivalent. Samples from 82 adult patients were included in the study: peripheral blood (n=39), lymph node suspensions (n=21), bone marrow (n=5) or different tissues (n=17, cerebrospinal, seroma, pleural and ascite fluid, spleen). The diagnoses included diffuse large B-cell lymphoma (DLCBL, n=33 with 4 DLBCL of central nervous system (CNS)), Sezary syndrome (SS, n=14), peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS, n=11), T-cell prolymphocytic leukaemia (T-PLL, n=8), enteropathy-associated T-cell lymphoma (EATL-1, n=2), angio-immunoblastic lymphoma (AITL, n=5), primary effusion lymphoma (PEL, n=1), plasmablastic lymphoma (PBL, n=1), B-lymphoblastic lymphoma (B-LBL, n=1), breast implant associated anaplastic large cell lymphoma (BIA-ALCL, n=1), anaplastic large cell lymphoma (ALCL, n=1), mantle cell lymphoma (n=1), T-cell large granular lymphocyte leukemia (T-LGLL, n=2) and chronic lymphoproliferative disorders of NK cells (CLPD-NK, n=1). Four groups are defined: (1) a negative group (n=60) presents nMFI30 10% with the 3 FCM Abs and positive in IHC (2 ALCL, 1 DLBCL, 1 EATL). This group shows a more intense nMFI30 with BC Ab; (3) a dim positive group (n=8) presents nMFI30 between 1-10% with the 3 FCM Abs. In this group, IHC is negative in 2 out of the 3 tested cases; (4) a discordant group (n=10) presents nMFI30 >1% with at least 1 Ab and discordant with another one. In this group, 8 IHC were tested: 2 IHC positive 1% with Ancell Ab and 1 case shows a high discrepancy between 2 FCM Abs. Regarding lymphoma entities, T-PLL, DLBCL-CNS, and T-LGLL are always negative and the ALCL are positive. Seven out of the 33 DLBCL are in the positive or discordant groups (21%). Conclusion As previously reported in literature using IHC, CD30 is positive in all ALCL, in some DLCBL (20%) and only rarely in other NHL using FCM. Therefore these first results emphasize the feasibility of FCM in CD30 determination and quantification in NHL subtypes and mainly its multicentric standardization. The inclusion of FCM with relevant Abs in clinical trials using BV should be now validated in larger series to better understand clinical results. Figure. Figure. Disclosures Pruvot Debliquis: Alexion: Consultancy, Honoraria; Takeda Oncology: Honoraria. Baseggio:Takeda Oncology: Honoraria. Jacob:Takeda Oncology: Honoraria. Drenou:Takeda Oncology: Honoraria, Research Funding; Alexion: Consultancy, Honoraria.

Paroxysmal nocturnal hemoglobinuria (PNH) is currently diagnosed by flow cytometry; although highly sensitive, its interpretation and reporting appear as critical as its technique. Thus, we developed a quality control scheme for the French-speaking region based on the international recommendations for PNH screening.After a topical workshop, we proposed a 1-year, two-step survey program to any volunteering French-speaking clinical laboratory. The first survey consisted of sending raw data files to evaluate gating and the interpretation strategy of each center. The second stipulated sending fresh whole-blood samples to evaluate the whole process and its practice.Forty-nine participants from voluntary centers returned results for each of the two successive surveys. On virtual survey, 27% reported false-positive PNH created by immature granulocytes, whereas the minor PNH clone was not detected by 9%. On fresh survey, 63% of centers used at least the same six-color combination (CD24, CD14, CD33, CD15, CD45, and fluorescent aerolysin), and nearly 70% of participants were able to perform a sensitivity test less than 0.1% on neutrophils. All participants detected the major PNH clone, yet 16% returned false-positive results for the non-PNH clone case.We succeeded in rallying numerous French-speaking clinical laboratories for both surveys and in harmonizing the technical practice by highlighting common pitfalls.

Chronic lymphocytic leukemia (CLL) is a clonal malignancy of mature B cells that displays a great clinical heterogeneity, with many patients having an indolent disease that will not require intervention for many years, while others present an aggressive and symptomatic leukemia requiring immediate treatment. Although there is no cure for CLL, the disease is treatable and current standard chemotherapy regimens have been shown to prolong survival. Recent advances in our understanding of the biology of CLL have led to the identification of numerous cellular and molecular markers with potential diagnostic, prognostic and therapeutic significance. We have used the recently developed digital multiplexed gene-expression technique (DMGE) to analyze a cohort of 30 CLL patients for the presence of specific genes with known diagnostic and prognostic potential. Starting from a set of 290 genes we were able to develop a molecular signature, based on the analysis of 13 genes, which allows distinguishing CLL from normal peripheral blood and from normal B cells, and a second signature based on 24 genes, which distinguishes mutated from unmutated cases (LymphCLL Mut). A third classifier (LymphCLL Diag), based on a 44-gene signature, distinguished CLL cases from a series of other B-cell chronic lymphoproliferative disorders (n = 51). While the methodology presented here has the potential to provide a "ready to use" classification tool in routine diagnostics and clinical trials, application to larger sample numbers are still needed and should provide further insights about its robustness and utility in clinical practice.

Introduction La detection d’une atteinte meningee par ponction lombaire (PL) permet d’etablir le diagnostic et le suivi des lymphomes oculocerebraux (LOC). Objectifs Evaluer l’apport des analyses du liquide cephalorachidien (LCR) par cytologie conventionnelle (CC), cytometrie en flux (CMF) et par dosage de l’Interleukine 10 (IL10) pour le diagnostic des LOC. Patients et methodes Seize patients atteints de LOC a la presentation initiale, PL par aiguilles atraumatiques (22G), 8 mL de LCR reserves pour la CC et la CMF, delai moyen PL-analyse au laboratoire 90 minutes En cas de negativite une 2eme PL a ete effectuee dans la mesure du possible : moyenne 1,6 LCR par patient. IL 10 mesure sur LCR, technique CBA (Cytometric Bead Array ; BD Biosciences), limite de detection 2,5 pg/mL. Resultats La CC a la 1ere PL etait positive (p) pour 3 patients, suspecte (s) pour 3, negative (n) pour 10 ; a la PL de controle 4p, 1s, 4n. Au total 7/16 patients positifs (44 %) et 3/16 suspects (19 %). La CMF a la 1ere PL a revele 5p, 2s, 9n ; la PL de controle 3p, 1s, 4n. Au total 8/16 patients positifs (50 %) et 1 suspecte (6 %). IL10 > 4 pg/mL : 15 ; Discussion Nos resultats montrent que la CC/CMF associee au dosage des IL10 effectuees de maniere standardisee permet de diagnostiquer une atteinte meningee chez 50 % des patients a la presentation initiale. L’IL10 apporte des arguments supplementaires en faveur d’un lymphome pour la plupart des patients negatifs en CC/CMF. Conclusion Un bilan LCR structure et effectue par une equipe experimentee permet diagnostiquer des atteintes meningees des lymphomes dans 50 % des cas. Associee a une imagerie « classique » de lymphome elle permet de poser le diagnostic sans biopsie.

A new entity of acute leukemia coexpressing CD4(+)CD56(+) markers without any other lineage-specific markers has been identified recently as arising from lymphoid-related plasmacytoid dendritic cells (pDCs). In our laboratory, cells from a patient with such CD4(+)CD56(+) lineage-negative leukemia were unexpectedly found to also express the myeloid marker CD33. To confirm the diagnosis of pDC leukemia despite the CD33 expression, we demonstrated that the leukemic cells indeed exhibited pDC phenotypic and functional properties. In 7 of 8 other patients with CD4(+)CD56(+) pDC malignancies, we were able to confirm that the tumor cells expressed CD33 although with variable expression levels. CD33 expression was shown by flow cytometry, reverse transcriptase-polymerase chain reaction, and immunoblot analysis. Furthermore, CD33 monoclonal antibody stimulation of purified CD4(+)CD56(+) leukemic cells led to cytokine secretion, thus confirming the presence of a functional CD33 on these leukemic cells. Moreover, we found that circulating pDCs in healthy individuals also weakly express CD33. Overall, our results demonstrate that the expression of CD33 on CD4(+)CD56(+) lineage-negative cells should not exclude the diagnosis of pDC leukemia and underline that pDC-specific markers should be used at diagnosis for CD4(+)CD56(+) malignancies.