Measurable residual disease (MRD) follow-up is recommended for treatment response evaluation in acute myeloid leukemia (AML) clinical trials according to ELN 2025 guidelines. The aim of this study was to implement a standardized follow-up of patients using a harmonized MRD flow approach across 30 French hematology laboratories participating in AML clinical trials. To obtain comparable results, the network established recommendations from wet-lab procedures to clinical reports. We designed a 3-tube panel with mandatory 8-color common markers per tube, according to ELN recommendations, to identify leukemia-associated immunophenotype/different-from-normal (LAIP/DfN) patterns in bulk cells and leukemic stem cell (LSC)-enriched populations in the CD34+CD38- fraction. A backbone of CD34/CD38/CD45/CD117 was used, completed by lineage markers for the first tube, LSC-associated markers for the second tube, and monocytic and differentiation markers for the third tube. This panel can be used in 8-, 10-, and 12-color formats and implemented on multiple conventional flow cytometer platforms. We propose flow cytometer settings adapted to each platform. Harmonization of sensitivity between the four platforms was performed using 8-peak rainbow beads. Immunostaining was performed after bulk lysis. To detect bias between platforms, the staining index was tested using fresh healthy bone marrow samples in parallel on the four platforms. Regular bone marrow quality-control samples were shared among laboratories for wet external quality assessment (EQA) to verify all steps of the protocol. Finally, standardization of the data analysis strategy obtained in the centers was evaluated using dry EQA by sharing MRD FCS data files. The feasibility of this multicenter approach requires harmonization of instrument sensitivity and sample preparation, as well as training and systematic education of analytical operators.

Abstract Background During their care pathway, AML patients not admitted to Specialized Haematology Units (SHU) have less access to curative treatment. We aim to determine whether access to optimal curative treatment is affected by sociodemographic factors. Methods We included 1,033 incidents AML-cases diagnosed between 2012–2016 from three French “départements”. We considered patients managed in reference hospitals SHU within 5 days(n = 297) received “gold-standard” treatment. Treatment was "curative-treatment” if intensive chemotherapy and “non-curative” otherwise. Firstly, we trained a Gradian Boosting Machine (GBM) algorithm on 80%(n = 238) of "gold-standard" cases to learn how they were treated and validated the model on the remaining 20%(n = 59). Next, GBM predictions were contrasted with actual treatment. Using multivariable logistic regression, we examined how non-optimal treatment (discrepancy between predicted curative and observed non-curative treatment) was associated with sociodemographic factors. Patients with predicted non-curative treatment were excluded as uninformative on access to curative treatment (n = 471). Results The rate of “curative treatment” was 84.8% (252/297) for gold-standard patients vs. 33.5% (247/736) for others. The three most influential predictive factors in gold-standard patients were age (68.3%-influence), t-AML/MDS (15.8%), and the AML-others subtypes (5.4%). A total of n = 102(9.9%) patients were in non-optimal treatments. Living in Basse-Normandie (0.65-times;95%CI [0.5,0.8]) and over 30minutes from a reference hospital were strongly associated with a non-optimal treatment. Conclusions There are geographical disparities in access to optimal treatment, potentially linked to medical desert situations or medical system organization.

Background: The excess mortality observed in Acute Myeloblastic Leukaemia (AML) patients, partly attributed to unequal access to curative treatments, could be linked to care pathways.Methods: We included 1039 AML incident cases diagnosed between 2012-2016 from the 3 French blood cancer registries (3,625,400 inhabitants). We describe patients according to age, the medical entry unit and access to the specialised haematology unit (SHU) during follow-up. Multivariate logistic regression model was done to determine the association between covariables and access to SHU. A total of 713 patients (69%) had access to SHU during care.Results: The most common care pathway concerned referral from the general practitioner to SHU, n = 459(44%). The univariate analysis observed a downward trend for the most deprived patients. Patients who consulted in SHU were younger (66 years vs. 83, p < 0.001), and 92% had access to cytogenetic analysis (vs. 54%, p < 0.001). They also had less poor prognosis AML-subtypes (AML-MRC, t-AML/MDS and AML-NOS) (38% vs. 69%); 77% with de novo AML (vs. 67%, p < 0.003)], more favourable cytogenetic prognostic status (23% vs. 6%, p < 0.001), less comorbidities (no comorbidity = 55% vs. 34%, p < 0.001) and treatments proposed were curative 68% (vs. 5.3%, p < 0.001). Factors limiting access to SHU were age over 80 years (OR, 0.14; 95% CI, 0.04-0.38), severe comorbidities (OR, 0.39; 95% CI, 0.21-0.69), emergency unit referral (OR, 0.28; 95% CI, 0.18-0.44) and non-SHU referral (OR, 0.12; 95% CI, 0.07-0.18). Consultation in an academic hospital increased access to SHU by 8.87 times (95% CI, 5.64-14.2).Conclusion: The high proportion of access to cytogenetic testing and curative treatment among patients admitted to SHU, and the importance of early treatment in AML underlines the importance of access to SHU for both diagnosis and treatment.

Introduction Blastic plasmacytoid dendritic cell neoplasms (BPDCN) are now well-characterized diseases clearly referenced in the 5 th edition of the World Health Organization (WHO) Classification of Tumors (2022) 1 but treatment remains a real challenge. There is no consensus on the first line treatment even if CD123 targeted therapies are available in the USA and some European countries. Standard chemotherapy remains largely used as first line treatment with better results of leukemia-based regimens despite a high toxicity rate in this frail population 2,3. To establish a reference chemotherapy scheme, we prospectively evaluated the efficacy and toxicity of a combination chemotherapy (idarubicin, methotrexate, L-asparaginase, and dexamethasone) in newly diagnosed BPDCN patients (pts) in France. Patients and methods This single stage phase II study enrolled consecutive adult pts with suspected BPDCN in participating French centers. BPDCN diagnosis was centrally reviewed for cytology and immunophenotype (IF) (Pr Garnache Ottou F, UMR RIGHT BESANCON) and if needed for histology (Dr Petrella T, Montréal, Canada) according to published recommendations 1,4. After giving their informed consent, patients were evaluated for tumoral involvement by PET-scan, systematic lumbar puncture, and the mSWAT score was calculated for skin extension. Patients then received three 21 days-cycles of Ida/Metho/L-asp/Dex combination, before evaluation. Eligible patients with complete response (CR), complete response with incomplete bone marrow recovery (CRi) or partial response (PR) underwent allogeneic hematopoietic stem cell transplantation (HCT). Those not eligible received consolidation chemotherapy with 28 days cycles of Metho/L-asp/Dex (Figure 1). The primary objective was the proportion of patients with CR after 3 cycles of chemotherapy. Secondary objectives were the proportion of patients with an objective response (ORR) defined as CR, CRi or PR, the minimal residual disease (MRD) in responding patients evaluated by the presence of plasmacytoid dendritic cell blast measured by flow cytometry in the bone marrow, the incidence of severe adverse events and overall survival (OS). The competent ethics committee (Comité de Protection des Personnes Île de France 8) approved the study. The Besançon University hospital promoted the trial, financed by a grant of the French National Cancer Institute (INCa-DGOS_11093). Results Twenty-eight pts, originating from 16 centers, were screened between May 2019 and March 2023. Two patients with a misdiagnosis were screen failures. Two patients did not receive the planned chemotherapy due to clinical deterioration; 24 patients (21 male, 3 female) received at least one chemotherapy cycle and 23 are analyzed with a current end-point on June 30, 2023. Median age was 65y (21-79y). ECOG status was 0-1 in 20 cases, and 2 in 3 cases. A cutaneous involvement was identified in 16 pts (70%) and an extra medullary involvement was present in 13 (62%) pts: spleen, n= 6 (25%); lymph nodes, n= 7 (30%). Twenty-three pts (90%) had a bone marrow infiltration (identified only on IF in 4 cases), and 3 cases (14%) a documented central nervous system involvement. Nine pts had to stop planned treatment due to severe adverse events (3 deaths, 4 acute renal failure and 2 grade 4 febrile neutropenia) and in 4 pts, at least one cycle had to be delayed. Among the 15 pts receiving at least 3 cycles, 12 (80% and 50% of the whole cohort) were in ORR (CR = 8, CRi = 2, PR = 2) after the 3rd cycle of chemotherapy, 2 pts did not respond. Eight of ten (80%) CR/CRi pts had a MRD < 10 -4 without any further relapse. Nine of 12 responding patients (75%) received an allogeneic HCT 1-2 months after the end of the 3 rd cycle. Global OS at 6 months for responding or failing pts were 100% and 37% respectively (Figure 2). Conclusion In selected pts, an adapted chemotherapy could offer high CR rate in pts able to follow the planned treatment but remains toxic in frail pts, with only half of the them achieving a 3 rd cycle of chemotherapy. We confirm that pts achieving ORR and receiving HCT obtain prolonged CR. MRD level seems to correlate with OS and could be a useful tool to manage treatment toxicity in BPDCN frail pts. References: 1. Khoury JD et al., Leukemia (2022) Jul;36(7):1703-1719 2. Laribi et al. Blood Adv (2020) 4 (19): 4838-4848. 3. Garnache-Ottou et al., Blood Adv (2019) 3 (24): 4238 4. Philippe L et al., Haematologica (2017) ; Nov;102(11):1861-1868

Topic: 4. Acute myeloid leukemia - Clinical Background: AML patients not admitted to specialised haematology unit (SHU) during their care pathway have less access to curative treatment. Aims: Our aim is to determine whether access to optimal curative treatment is based on the patient’s clinico-biological characteristics or affected by non-biological factors. Methods: Patients were described according to their treatment modalities (curative, non-curative and untreated). In 1000 times bootstrapping process, we trained machine learning (ML) algorithms to learn the clinico-biological characteristics that were used to decide the treatment modalities of AML gold standard patient (treated in academic hospitals by haematologists within 5 days of their diagnosis, n=297). Based on the ML model predictions, we create two groups of patients: optimal treatment patient (predicted as treated and effectively treated) versus non-optimal treatment patients (predicted as treated but effectively untreated). Then after, a multivariate logistic regression model was used to determine the non-biological factors associated with non-optimal treatments. Finally, the mean of the 1000 estimates was used as the Odds Ratio. Results: In our study, 499 patients (n=48.03%), 273 (26.28%) and 261 (25.12%) had respectively received curative, non-intensive and no treatment. The 3 most influential factors in the choice of treatment modalities were age (61.24% influence), secondary aspect of AML/MDS (21.43%) and presence of severe comorbidities (4.95%). In total, n=460 (44.5%) had received optimal treatment and n=101 (9.8%) received non-optimal treatment. Factors associated with non-optimal treatment were: living in Basse-Normandie (0.63 times) and living in a municipality located between 30 and 100km of an academic hospital. Summary/Conclusion: We show that non-biological factors, in particular geographical disparities have an impact on access to optimal curative treatment. This may be related to geographical disparities in the organisation of the AML care pathway or potentially to the situation of a geographical medical desert, which needs to be studied in more detail.Keywords: Artificial intelligence, Population, Acute myeloid leukemia, Epidemiology

The analysis of biological fluids is crucial for the diagnosis and monitoring of diseases causing effusions and helps in the diagnosis of infectious diseases. The gold standard method for cell count in biological fluids is the manual method using counting chambers. The microbiological routine procedures consist of Direct Gram staining and culture on solid or liquid media. We evaluate the analytical performance of SYSMEX UF4000 (Sysmex, Kobe, Japan) and Sysmex XN10 (Sysmex, Kobe, Japan) in comparison with cytological and microbiological routine procedures. A total of 526 biological fluid samples were included in this study (42 ascitic, 31 pleural, 31 peritoneal, 125 cerebrospinal, 281 synovial, and 16 peritoneal dialysis fluids). All samples were analysed by flow cytometry and subsequently processed following cytological and/or microbiological routine procedures. With regards to cell counts, UF4000 (Sysmex, Kobe, Japan) showed a performance which was at least equivalent to those of the reference methods and superior to those of XN10 (Sysmex, Kobe, Japan). Moreover, the bacterial count obtained with UF4000 (Sysmex, Kobe, Japan) was significantly higher among culture or Direct Gram stain positive samples. We established 3 optimal cut-off points to predict Direct Gram stain positive samples for peritoneal (465.0 bacteria/μL), synovial (1200.0 bacteria/μL), and cerebrospinal fluids (17.2 bacteria/μL) with maximum sensitivity and negative predictive values. Cell count and detection of bacteria by flow cytometry could be used upstream cytological and microbiological routine procedures to improve and accelerate the diagnosis of infection of biological fluid samples.

Introduction: MRD follow-up is now mandatory for treatment response evaluation in AML clinical trials (ELN 2017 and 2021 guidelines: Heuser et al,Blood doi:10.1182/blood.2021013626.). Beside to molecular biology methods, multiparameter flow cytometry assay represents the most reliable approach. The aim of this study was to implement an harmonized follow up of the patients using a standardized MRD flow approach across 30 French hematology laboratories participating in AML clinical trials. Methods: To obtain superposable results, the network has established recommendations from Wet labs procedure to clinical reports using common panels, flow cytometers settings and analysis strategy. We designed a 2-tubes panel with minimal mandatory 8c markers by tube, according to ELN recommendations to identify the pattern of LAIP/DfN in bulk cells and the LSC (Leukemia Stem Cells) in CD34+CD38- fraction. A « backbone » CD34/CD38/CD45/CD117 was used, completed by CD7,CD56, CD13, CD33, CD19 for the 1st tube and CD90(Thy-1), Mix (CD97+CLL1+TIM3), CD123, CD45RA for the 2nd one. This panel could be used in 8c,10c,12c (HLADR, CD36, CD10, CD200) implemented on Becton Dickinson (CANTO and LYRIC) or Beckman Coulter (NAVIOS and DxFlex) cytometers (Fig 1A). Harmonization of the sensitivity between platforms (18 BD and 12 BC) was performed using 8 Picks Rainbows calibration beads. Immunostaining was performed after "bulk" lysis technique (NH4Cl). A total of minimal 500 000 cells was acquired in each tube and data were analyzed using DIVA/FACSUITE and KALUZA software. Results: To detect any bias between the platforms, firstly we tested 10 EDTA fresh regenerative marrow samples in parallel at 2 platforms (CANTO and NAVIOS). Similarity of the staining index between positive and negative population were compared between the samples and the 2 platforms showing no differences. Secondly, regular QC (Quality Control Sample), of normal bone marrow (from healthy donor) 1/year (a total of 5 since 2017) was shared among the participants centers(Fig1B).The specific events populations (nHSC, MPP, LMPP"like,etc) were evaluated by centers using a common gating strategy. In a third step, standardization of the data analysis strategy obtained in the centers was subsequently evaluated using a virtual quality control(CQA) by sharing MRD FCS data files. About 90% of the locally analyzed data were included in an interval centralized on the average of the series mean +/- 2 SD. During the follow up of the patients, a series of 18 Web educational meeting was implemented to review and validate cases with difficulties regarding analysis interpretation and confrontation with molecular MRD (transcripts, NPM1, WT1, NGS) and also chimerism in allograft follow-up (mainly cases with clonal hematopoiesis or stressed bone marrow). Finally, the harmonized data generated in our group allowed to perform a Computer aided design (CAD) in assessment of AML MRD flow using proprietary developed R script based upon FlowSom. It performs an automated definition of metacluster with abnormal population (by comparison to a set of reference bone marrow) which are quantified in the CD34+ CD117+ space for all samples (diagnosis, follow up and references marrow). It then extracts the metacluster significantly different from that observed for the reference samples (> mean+6sd. It calculates the MRD in % of WBC CD45+. The limits of sensitivity of the CAD method shows that a MRD remains evaluable by CAD up to 0.04% (50 events in 1 000 000). We compared the results between the conventional and the CAD method on 60 MRD samples. The slope of the correlation line was 0.95 with an R2 of 0.97 (Fig 1C). Using the definition threshold of a positive MRD at 0.1%, the agreement of the results between the two methods was evaluated by the Cohen kappa coefficient of 0.87. Conclusions: This methodological validation protocol is a mandatory step to consider the use of MRD flow in AML clinical trials. Choosing a multicentric approach could be challenging, but our first results are promising and showed the feasibility of this concept when: (i) a straight harmonisation of the instruments sensitivity and samples preparation are established, and (ii) training and systematic education among the analytical operators are regularly performed. Finally, our pilot study shows a very strong correlation between conventional method and unsupervised analyses using data generated by the multicentric network. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Hairy cell leukemia (cHCL) patients have, in most cases, a specific clinical and biological presentation with splenomegaly, anemia, leukopenia, neutropenia, monocytopenia and/or thrombocytopenia, identification of hairy cells that express CD103, CD123, CD25, CD11c and identification of the V600E mutation in the B-Raf proto-oncogene (BRAF) in 90% of cases. Monocytopenia is absent in vHCL and SDRPL patients and the abnormal cells do not express CD25 or CD123 and do not present the BRAFV600E mutation. Ten percent of cHCL patients are BRAFWT and the distinction between cHCL and HCL-like disorders including the variant form of HCL (vHCL) and splenic diffuse red pulp lymphoma (SDRPL) can be challenging. We performed deep sequencing in a large cohort of 84 cHCL and 16 HCL-like disorders to improve insights into the pathogenesis of the diseases. BRAF mutations were detected in 76/82 patients of cHCL (93%) and additional mutations were identified in Krüppel-like Factor 2 (KLF2) in 19 patients (23%) or CDKN1B in 6 patients (7.5%). Some KLF2 genetic alterations were localized on the cytidine deaminase (AID) consensus motif, suggesting AID-induced mutations. When analyzing sequential samples, a clonal evolution was identified in half of the cHCL patients (6/12 pts). Among the 16 patients with HCL-like disorders, we observed an enrichment of MAP2K1 mutations in vHCL/SDRPL (3/5 pts) and genes involved in the epigenetic regulation (KDM6A, EZH2, CREBBP, ARID1A) (3/5 pts). Furthermore, MAP2K1 mutations were associated with a bad prognosis and a shorter time to next treatment (TTNT) and progression-free survival (PFS), independently of the HCL classification.

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.

Hairy cell leukemia (HCL) is characterized by abnormal villous lymphoid cells that express CD103, CD123, CD25 and CD11c. HCL-like disorders, including hairy cell leukemia variant (vHCL) and splenic diffuse red pulp lymphoma (SDRPL), have similar morphologic criteria and a distinct phenotypic and genetic profile. We investigated the immunophenotypic features of a large cohort of 82 patients: 68 classical HCL, 5 vHCL/SDRPL and 9 HCL-like NOS. The HCL immunophenotype was heterogeneous: positive CD5 expression in 7/68 (10%), CD10 in 12/68 (18%), CD38 in 24/67 (36%), CD23 in 22/68 (32%) and CD43 in 19/65 (31%) patients. CD26 was expressed in 35/36 (97%) of HCL patients, none of vHCL/SDRPL and one of seven HCL-like NOS (14%). When adding CD26 to the immunologic HCL scoring system (one point for CD103, CD123, CD25, CD11c and CD26), the specificity was improved, increasing from 78.6% to 100%. We used unsupervised analysis of flow cytometry raw data (median fluorescence, percentage of expression) and the mutational profile of BRAF, MAP2K1 and KLF2. The analysis showed good separation between HCL and vHCL/SDRPL. The HCL score is not sufficient, and the use of unsupervised analysis could be promising to achieve a distinction between HCL and HCL-like disorders. However, these preliminary results have to be confirmed in a further study with a higher number of patients.

AbstractIntroductionSince 2009, multiple randomized trials have shown faster and deeper responses in CML patients treated with new‐generation TKI (NG‐TKI) compared to those treated with imatinib (IM). Are the same results observed in the general population?Materials and MethodsPatients were identified from the three French hematological malignancies population‐based registries. All CML patients (ICD‐O‐3: 9875/3) diagnosed between 2006 and 2016 and resided in registries areas were included. The TKI generation effect on achievement of MMR in first‐line therapy was assessed through a multivariate competitive risk analysis. An alluvial plot described the pathways leading to death.ResultsIn total, 507 CML patients received TKI in first‐line treatment, 22% were enrolled in a clinical trial. After adjustment, NG‐TKI patients were significantly more likely to achieve MMR during first‐line therapy than IM patients (HR: 1.88 CI95% [1.35–2.61]). At the end of follow‐up, 212 patients were still in first‐line therapy (46 of them died), 203 switched to second‐line (43 subsequently died), 26 were on TFR from first‐line (4 subsequently died), and 20 stopped their treatment (16 subsequently died).DiscussionIn this comprehensive real‐life setting, the results were consistent with clinical trials. The results are not sufficient to conclude that a NG‐TKI treatment is superior with regard to these patients, despite indications regarding differences between the TKI generation effect on survival and tolerance.

Abstract Introduction Allogeneic Hematopoietic Cell Transplantation (allo-HCT) has proved its efficiency in reducing Acute Myeloid Leukemia (AML) recurrence, although it was associated with high rates of complications especially in older patients. The worldwide number of allo-HCT has increased within 35 years, from 10.000 transplantations before 1985 to over a million in 2012. The decision to perform transplantation depends on the estimated risk-benefit ratio. High-risk prognostic factors include cytogenetics, age at diagnosis, presence of comorbidities and the response to treatment. By using combination of risk factors, international recommendations have been published to harmonize AML care and maximize the benefit of using allo-HCT. The principal aim of this study is to describe real life AML care management in all consecutive patients diagnosed and registered on 3 regional cancer registries in France, to analyze their outcome after different therapeutic strategies, following or not the international recommendations. Method This retrospective study included all AML patients diagnosed between January 2012 and December 2016 reported to the French population data-based of regional cancer registries specialized in hematological malignancies. Allo-HCT data were extracted from the Société Française de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) registry. Two groups of patients were defined according to the treatment received: i) group 1, patients who have received the best recommended care including allo-HCT considering HLA compatibility and best donor choice or best conventional treatment according to therapeutic guidelines based on individuals and clinical characteristics from The American Society for Blood and Marrow Transplantation guidance; ii) group 2, patients who received a treatment outside the recommendations. To study the impact of therapeutic decision on overall survival, a case-control study was performed using a one for one matching between group 1 and group 2. An exact matching on individual and disease characteristics (cytogenetic risk, Charlson score class, age group at diagnosis, subtype AML and response to treatment) allowed to pair-match patients following or not the international recommendations for therapeutic strategy. Net survival was estimated until five-year using non-parametric Pohar-Perme estimator (survival distribution compared using Grafféo test). Results A total of 1039 AML patients diagnosed from 2012 to 2016 were identified, 449 (43 %) received a curative treatment and 540 patients a non-curative treatment (hypomethylating agents, low dose of cytarabine or other palliative treatment, best supportive care combined to no effective treatment). Based on available clinical data, 430 patients were included in the study. Group 1 included 296 patients (68%), 167 males and 129 females with 54 receiving allo-HCT (32 geno-identical and 22 unrelated). Group 2 included 134 patients (31%), 72 males and 62 females with 94 receiving allo-HCT (14 geno-identical, 50 unrelated and 30 mismatched). In patients for whom allo-HCT represented the best option according to the recommendations (Figure B, n = 44), a very significant lower survival was observed in patients who did not receive allo-HCT when they were compared to patients who received allo-HCT, with a 5 year-overall survival probability of 7 % and 50 % respectively (p= 0.019). In patients for whom allo-HCT was not recommended (Figure A, n = 42), we did not observe any significant difference of survival between patients transplanted or not. Conclusion This analysis shows the importance of allo-HCT decision in AML patients, especially when following international guidelines. Although individual risks factors have been previously studied, our analysis sums up theses factors and allow to understand the importance of integrating allo-HCT in the therapeutic strategy of AML and to re-evaluate current practices and its impact on patient outcome. Figure 1 Figure 1. Disclosures Pigneux: Roche: Consultancy, Research Funding; BMS Celgene: Consultancy, Research Funding; Sunesis: Consultancy, Research Funding; Amgen: Consultancy; Novartis: Consultancy, Research Funding. Forcade: Novartis: Other: travel grant. Mohty: Pfizer: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Jazz: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Astellas: Honoraria; Amgen: Honoraria; Sanofi: Honoraria, Research Funding; Adaptive Biotechnologies: Honoraria. Dulery: Novartis: Honoraria; Takeda: Consultancy; Gilead: Other: Travel support and registration fees for scientific meetings .

Les immunophénotypages réalisés par cytométrie en flux (CMF), pour le diagnostic des hémopathies malignes et des désordres immunitaires, sont soumis aux exigences de la norme NF EN ISO 15189 portant sur les phases pré-, per- et post- analytiques. Le format des comptes-rendus de résultats apparaît très hétérogène selon les laboratoires, avec un besoin d’harmonisation exprimé par les cytométristes et les cliniciens destinataires. Nous avons initié une enquête au sein du groupe FranceFlow et relayée par le groupe CytHem, afin de faire un « état des lieux » des pratiques et avons recueilli 54 réponses. Nous avons ensuite constitué un groupe de travail (GT) réunissant 32 centres afin de réfléchir à des propositions consensuelles d’harmonisation. Cet article présente les résultats de cette enquête et les propositions émanant du GT. Plus qu’un effort collectif d’harmonisation, ce document constitue une opportunité de revisiter et moderniser le format de rendu des résultats sur lequel le biologiste pourra s’appuyer pour justifier ses choix.

International Journal of Laboratory HematologyVolume 43, Issue 5 p. e261-e263 LETTER TO THE EDITOR The structural parameters and flags of the Sysmex XN™ analyser: Are they discriminative between reactive and malignant lymphocytosis in the context of lymphocyte counts above 5 × 109/L in adults? Edouard Cornet, Edouard Cornet orcid.org/0000-0003-1667-3421 Laboratoire d'Hématologie, CHU Caen, Caen, FranceSearch for more papers by this authorEstelle Comte, Estelle Comte Laboratoire d’Hématologie cellulaire, GHS/Hospices Civils de Lyon, Pierre Bénite, FranceSearch for more papers by this authorLucile Baseggio, Corresponding Author Lucile Baseggio Lucile.baseggio@chu-lyon.fr orcid.org/0000-0001-7543-6480 Laboratoire d’Hématologie cellulaire, GHS/Hospices Civils de Lyon, Pierre Bénite, France Correspondence Lucile Baseggio, Laboratoire d’Hématologie Cellulaire/CBAPS, Groupement Hospitalier SUD/Hospices Civils de Lyon, 165 ch du grand Revoyet, 69495 PIERRE BENITE Cedex-France. Email: Lucile.baseggio@chu-lyon.frSearch for more papers by this author Edouard Cornet, Edouard Cornet orcid.org/0000-0003-1667-3421 Laboratoire d'Hématologie, CHU Caen, Caen, FranceSearch for more papers by this authorEstelle Comte, Estelle Comte Laboratoire d’Hématologie cellulaire, GHS/Hospices Civils de Lyon, Pierre Bénite, FranceSearch for more papers by this authorLucile Baseggio, Corresponding Author Lucile Baseggio Lucile.baseggio@chu-lyon.fr orcid.org/0000-0001-7543-6480 Laboratoire d’Hématologie cellulaire, GHS/Hospices Civils de Lyon, Pierre Bénite, France Correspondence Lucile Baseggio, Laboratoire d’Hématologie Cellulaire/CBAPS, Groupement Hospitalier SUD/Hospices Civils de Lyon, 165 ch du grand Revoyet, 69495 PIERRE BENITE Cedex-France. Email: Lucile.baseggio@chu-lyon.frSearch for more papers by this author First published: 12 June 2021 https://doi.org/10.1111/ijlh.13527Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume43, Issue5October 2021Pages e261-e263 RelatedInformation

DISEASE OVERVIEW:Hairy cell leukemia (HCL) and HCL-like disorders, including HCL variant (HCL-V) and splenic diffuse red pulp lymphoma (SDRPL), are a very heterogeneous group of mature lymphoid B-cell disorders characterized by the identification of hairy cells, a specific genetic profile, a different clinical course, and the need for appropriate treatment.DIAGNOSIS:Diagnosis of HCL is based on morphological evidence of hairy cells, an HCL immunologic score of 3 or 4 based on the CD11C, CD103, CD123, and CD25 expression, the trephine biopsy which makes it possible to specify the degree of tumoral medullary infiltration and the presence of BRAFV600E somatic mutation.RISK STRATIFICATION:Progression of patients with HCL is based on a large splenomegaly, leukocytosis, a high number of hairy cells in the peripheral blood, and the immunoglobulin heavy chain variable region gene mutational status. VH4-34-positive HCL cases are associated with a poor prognosis.TREATMENT:Patients should be treated only if HCL is symptomatic. Chemotherapy with risk adapted therapy purine analogs (PNAs) are indicated in first-line HCL patients. The use of chemo-immunotherapy combining PNAs and rituximab (R) represents an increasingly used therapeutic approach. Management of relapsed/refractory disease is based on the use of BRAF inhibitors (BRAFi) plus rituximab or MEK inhibitors (MEKi), recombinant immunoconjugates targeting CD22 or Bruton Tyrosine Kinase inhibitors (BTKi). However, the optimal sequence of the different treatments remains to be determined. The Bcl2-inhibitors (Bcl-2i) can play a major role in the future.

A 7 × 4 cm sized lesion of soft tissue in the right paraspinal region at the level of Th7 vertebra was accidentally discovered on a computed tomography scan in a 76yearold man. He did not present any abnormalities in the blood count (haemoglobin at 13.7 g/dL and platelet at 409 × 109/L). An exeresis was performed, and the haematoxylin and eosin staining of the mass (panel A, magnification ×10) revealed haematopoietic tissue containing myeloid, erythroid and megakaryocytic lines with maturation. The bone marrow aspiration (panel B, MGG, magnification ×100) showed a hypercellularity with dysplastic features mainly relating to the erythroid lineage. Perls staining on the bone marrow (panel D, magnification ×1000) found 74% ring sideroblasts. There were more than 100 megakaryocytes per slide, some of which were small and hyposegmented but not monolobated. In the blood, platelet anisocytosis was observed with the presence of macroplatelets. The karyotype was normal, and no BCRABL transcript was detected. Molecular investigations revealed mutations in CBL_ex9 (VAF: 39.5%); in JAK2_ex14 (V617F) (VAF 1%); and in SF3B1_ex14 (VAF: 44%). Eventually, Perls staining on the paravertebral mass showed deposits of haemosiderin iron (panel E, magnification ×40). Altogether, these features were compatible with

Les néoplasies myéloprolifératives chroniques, comme on doit les appeler maintenant, en dehors de la leucémie myéloïde chronique (LMC), ont fait l’objet de nombreux ajustements en termes de classification ce qui explique le peu de données disponibles sur leurs caractéristiques épidémiologiques. Cependant leur taux d’incidence standardisé sur la population mondiale montre que ce sont des maladies rares avec un chiffre variant de 1,7 pour la thrombocytémie essentielle (TE) à 0,3/100 000 habitants/an pour la myélofibrose primitive (MF). La survie nette à 5 ans est proche de 95% pour la polyglobulie de Vaquez (PV) et la TE mais reste de 55% pour la MF. L’incidence de la LMC est, elle, légèrement inférieure à 1 et stable depuis longtemps. En revanche l’arrivée des inhibiteurs de tyrosine kinase a révolutionné le pronostic et la survie nette à 5 ans est de plus de 80%.

There are limited population-based studies of hairy cell leukemia (HCL), a rare chronic lymphoproliferative disorder of B-cells. We conducted a population-based study that included all patients diagnosed with HCL between 1996 and 2016 in Western Normandy. Recorded data focused on medical history, clinical presentation, biological results, treatment modalities in the first line and in relapsed/refractory patients and the occurrence of secondary malignancies. One hundred and twenty-three HCL patients were registered in the database. HCL represented 0.7% of all malignant hematological disorders and 3.0% of all leukemia. The overall age-standardized incidence ratio (SIR) was 0.39/100,000 inhabitants in men and 0.09/100,000 in women, and it remained stable over the 20-year period analyzed. One hundred and seven patients (88%) received first-line treatment, 33 patients (27%) received at least 2 lines of treatment and 14 patients (11%) received more than 2 lines. Cladribine used as first-line treatment induced a high hematological complete response (HCR) rate of 92%. The median overall survival (OS) was over 15 years, with 5-year and 10-year survival rates of 84% and 70.5%. No significant differences in OS were observed between men and women, between the calendar periods studied or between patients who received a single line treatment with IFN-α or PNA. The risk of relapse was higher with IFN-α treatment, requiring subsequent treatments in that patients. The time to next treatment (TTN) tends to be longer for PNAs compared to IFN-α even if difference is not significant. Secondary cancers were observed in 9/123 patients (7.3%) with solid tumors in 8 patients and hematological malignancy in one patient. Our data confirm in real life that single courses of cladribine administered to patients with HCL induce high response rates, the majority of which are HCR. Relapses seem less frequent than with IFN-α and the administration schedule is less restrictive for the patients. The emergence of chemo-immunotherapy and the development of effective new drugs such as recombinant immunotoxins and BRAF targeting will offer new possibilities in the management of HCL patients.