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Contains fulltext : 290820.pdf (Publisher’s version ) (Open Access) Multiparameter flow cytometry (MFC) is one of the essential ancillary methods in bone marrow (BM) investigation of patients with cytopenia and suspected myelodysplastic syndrome (MDS). MFC can also be applied in the follow-up of MDS patients undergoing treatment. This document summarizes recommendations from the International/European Leukemia Net Working Group for Flow Cytometry in Myelodysplastic Syndromes (ELN iMDS Flow) on the analytical issues in MFC for the diagnostic work-up of MDS. Recommendations for the analysis of several BM cell subsets such as myeloid precursors, maturing granulocytic and monocytic components and erythropoiesis are given. A core set of 17 markers identified as independently related to a cytomorphologic diagnosis of myelodysplasia is suggested as mandatory for MFC evaluation of BM in a patient with cytopenia. A myeloid precursor cell (CD34(+) CD19(-) ) count >3% should be considered immunophenotypically indicative of myelodysplasia. However, MFC results should always be evaluated as part of an integrated hematopathology work-up. Looking forward, several machine-learning-based analytical tools of interest should be applied in parallel to conventional analytical methods to investigate their usefulness in integrated diagnostics, risk stratification, and potentially even in the evaluation of response to therapy, based on MFC data. In addition, compiling large uniform datasets is desirable, as most of the machine-learning-based methods tend to perform better with larger numbers of investigated samples, especially in such a heterogeneous disease as MDS. 01 januari 2023

Myeloid Derived Suppressive Cells (MDSC) are capable to suppress innate and adaptive immune responses, thus favouring solid cancer progression. However, little is known about the role of MDSC in acute myeloid leukaemia (AML). In this monocentric prospective study, 73 adult AML patients, eligible for first-line intensive chemotherapy, were included with the aim to study the influence on long-term outcomes of peripheral blood (PB) levels of monocytic (M) MDSC (M-MDSC) assessed by flow cytometry. A percentage of peripheral M-MDSC higher than 0.55% of leukocytes at diagnosis and a decrease of M-MDSC% after induction came out both as independent negative prognostic factors for leukaemia-free and overall survival.

Immunotherapy strategies relying on innate or adaptive immune components are increasingly used in onco-haematology. However, little is known about the infiltrated lymph nodes (LN) or bone marrow (BM) landscape of mantle cell lymphoma (MCL). The original transcriptomic approach of reverse transcriptase multiplex ligation-dependent probe amplification (RT-MLPA) was applied here to explore the expression of 24 genes of interest in MCL at diagnosis (21 LN and 15 BM) or relapse (18 LN). This allowed us to identify that at baseline, samples from MCL patients with an aggressive morphology (i.e. blastoid or pleomorphic) or a high proliferative profile, displayed significantly higher monocyte/macrophage-associated transcripts (

Hematological diagnostics is based on increasingly precise techniques of cellular and molecular analysis. The correct interpretation of the blood and bone marrow smears observed under an optical microscope still represents a cornerstone. Precise quantitative and qualitative cytomorphological criteria have recently been codified by up-to-date guidelines for diagnosing hematopoietic neoplasms. Morphological analysis has found formidable support in digital reproduction techniques, which have simplified the circulation of images for educational or consultation purposes. From 2007 to 2019, the Working Group WP10 of European LeukemiaNet (ELN) used, in annual exercises, digital images to support training in cytomorphology and verify harmonization and comparability in the interpretation of blood and bone marrow smears. We describe the design, development, and results of this program, which had 741 participants in-person or remotely, to which 2055 questions were submitted regarding the interpretation of cytomorphological images. We initially used circulation and presentation of digital microphotographs and then introduced a virtual microscopy (VM). Virtual slides were obtained using a whole slide imaging technique, similar to the one largely used in histopathology, to produce digitized scans of consecutive microscopic fields and reassembles them to obtain a complete virtual smear by stitching. Participants were required to identify cells in labeled fields of view of the virtual slides to obtain a morphological diagnosis. This work has demonstrated substantial improvements in diagnostic accuracy and harmonization with the VM technique. Between-observer concordance increased from 62.5% to 83.0%. The integrity of the digitalized film image, which provides a general context for cell abnormalities, was the main factor for this outcome.

Aging and senescence seem linked by fundamental, yet still ill-understood mechanisms. For this reason, this paper expands on the background of a discovery that still has to gain acknowledgement by public policies to find its place in a market hungry for a non-toxic anti-inflammatory molecule. Reversibility of the senescent cell phenotype was the starting-point of a research that turned out to identify the monoterpenes class of molecules as able to achieve this goal. Indeed, these compounds strongly inhibit the circulation of pro-inflammatory cytokines as well as the expression of cell-anchored adhesive molecules, liable to recruit activated immune cells. Starting from cell-based studies, the pre-clinical and clinical assays reported here confirmed the capacities of these compounds, both in experimental colitis, dermatitis and stress murine models, but also in-human studies addressing the latent chronic inflammation associated with age or psoriasis. Last but not least, because of an intriguing mechanism yet not totally unraveled and most probably depending on the effect of monoterpenes on gut microbiota strains–apart from assuring a constant gut barrier repair-a consistent Quality of Life amelioration, i.e. mood modulation probably due to enhanced dopamine secretion was also demonstrated. Finally, after entering in more pharmacologic considerations on toxicity and bio-availability studies as for the safety of this class of compounds, a strategic positioning of the precious role of anti-inflammatory drugs in a market that has yet to overcome common chronic diseases because of their predisposing condition not only to cancer and neuro-degenerative diseases but now also to COVID-19 is envisioned.

International audience

Contains fulltext : 290818.pdf (Publisher’s version ) (Open Access) BACKGROUND: Flow cytometry (FCM) aids the diagnosis and prognostic stratification of patients with suspected or confirmed myelodysplastic syndrome (MDS). Over the past few years, significant progress has been made in the FCM field concerning technical issues (including software and hardware) and pre-analytical procedures. METHODS: Recommendations are made based on the data and expert discussions generated from 13 yearly meetings of the European LeukemiaNet international MDS Flow working group. RESULTS: We report here on the experiences and recommendations concerning (1) the optimal methods of sample processing and handling, (2) antibody panels and fluorochromes, and (3) current hardware technologies. CONCLUSIONS: These recommendations will support and facilitate the appropriate application of FCM assays in the diagnostic workup of MDS patients. Further standardization and harmonization will be required to integrate FCM in MDS diagnostic evaluations in daily practice. 01 januari 2023

This cohort study assesses the incidence and severity of COVID-19 among vaccinated recipients of allogenic stem cell transplant in a single center after 1 or 2 messenger RNA booster doses during the Omicron wave in France.

Background: Despite therapeutic progress, 10 to 30% of adult patients with primary mediastinal B cell lymphoma (PMBCL) are primary refractory or experience early relapse (R/R). Allogeneic stem cell transplantation (allo-HSCT) thus remains a potentially curative option in this setting. Material and Methods: In this multicenter retrospective study, the outcomes of 33 French and Belgian adult patients allo-transplanted for R/R PMBCL between January 1999 and December 2018, were examined. Results: At allo-HSCT time, patients had received a median of 3 treatment lines, 50% of them were in complete response, 40% in partial response and 10% had a progressive disease. Forty-two percent of the donors were siblings and 39% matched related. The median follow-up for alive patients was 78 months (3.5-157). Considering the whole cohort, 2-year overall survival (OS), progression free survival (PFS) and graft-versus-host disease-free/relapse-free survival (GRFS) were 48% (95%CI: 33-70), 47% (95%CI: 33-68) and 38.5% (95%CI: 25-60) respectively. Cumulative incidence of relapse and non-relapse mortality rates were respectively 34% (95%CI: 18-50) and 18% (95%CI: 7-34). Disease status at transplant was the only factor predicting survivals, patients with progressive disease showing significant lower 2-year PFS (HR: 6.12, 95%CI: 1.32-28.31, p = 0.02) and OS (HR: 7.04, 95%CI: 1.52-32.75, p = 0.013). A plateau was observed for OS and PFS after 4 years with 10 patients alive after this date, suggesting that almost one third of the patients effectively salvaged and undergoing allo-SCT could be cured. Conclusion: This study indicates that allo-HSCT is a valid therapeutic option for R/R PMBCL, providing durable remissions.

This study reports the effectiveness of three injections of BNT162b2 anti-SARS-CoV-2 mRNA vaccine in 141 Allo-HSCT recipients with a median follow-up of 6 months post-third shot. We demonstrate a long-term high protection of Allo-HSCT recipients since only 2 infections and one death related to COVID-19 occurred.

Immune thrombocytopenia (ITP) is an acquired bleeding disorder, for which no specific diagnostic test exists. Inherited thrombocytopenia (IT) can mimic ITP and lead to unappropriated management with significant morbidity. Here, in small cohorts of these two disorders, we explored whether platelet sialylation and platelet activation could allow to discriminate the two conditions. We also aimed to confirm the value of immature platelet counts in this discrimination. Platelet sialylation and the expression level of P-selectin were assessed by multiparameter flow cytometry. Immature platelets were estimated on a Sysmex XN 9000 analyzer. No significant difference in platelet sialylation was observed between ITP and IT. Contrarily, platelet activation was significantly higher in ITP patients (p = 0.008). The immature platelet fraction, as previously demonstrated, was significantly lower in the ITP group compared to the IT group (p = 0.014). That statistical significance was achieved in this small pilot study suggests that the two easily available assays of immature platelet count and P-selectin expression could help physicians to reach the proper diagnosis in complex cases of thrombocytopenia.

Plasmacytoid dendritic cells (PDC) constitute a small subset of normal bone marrow (BM) cells but have also been shown to be present, sometimes in large numbers, in several hematological malignancies such as acute myeloid leukemia with RUNX1 mutation, chronic myelomonocytic leukemia or, obviously, blastic plasmacytoid dendritic cell neoplasms. These cells have been reported to display somewhat variable immunophenotypic features in different conditions. However, little is known of their plasticity within individual patients. Using an unsupervised clustering tool (FlowSOM) to re-visit flow cytometry results of seven previously analyzed cases of hematological malignancies (6 acute myeloid leukemia and one chronic myelomonocytic leukemia) with a PDC contingent, we report here on the unexpectedly high variability of PDC subsets. Although five of the studied patients harbored a RUNX1 mutation, no consistent feature of PDCs could be disclosed as associated with this variant. Moreover, the one normal single-node small subset of PDC detected in the merged file of six normal BM could be retrieved in the remission BM samples of three successfully treated patients. This study highlights the capacity of unsupervised flow cytometry analysis to delineate cell subsets not detectable with classical supervised tools.

International audience; Ever since hematopoietic cells became "events" enumerated and characterized in suspension by cell counters or flow cytometers, researchers and engineers have strived to refine the acquisition and display of the electronic signals generated. A large array of solutions was then developed to identify at best the numerous cell subsets that can be delineated, notably among hematopoietic cells. As instruments became more and more stable and robust, the focus moved to analytic software. Almost concomitantly, the capacity increased to use large panels (both with mass and classical cytometry) and to apply artificial intelligence/machine learning for their analysis. The combination of these concepts raised new analytical possibilities, opening an unprecedented field of subtle exploration for many conditions, including hematopoiesis and hematological disorders. In this review, the general concepts and progress achieved in the development of new analytical approaches for exploring high-dimensional data sets at the single-cell level will be described as they appeared over the past few years. A larger and more practical part will detail the various steps that need to be mastered, both in data acquisition and in the preanalytical check of data files. Finally, a step-by-step explanation of the solution in development to combine the Bioconductor clustering algorithm FlowSOM and the popular and widely used software Kaluza® (Beckman Coulter) will be presented. The aim of this review was to point out that the day when these progresses will reach routine hematology laboratories does not seem so far away

International audience; DNA methylation, a major biological process regulating the transcription, contributes to the pathophysiology of hematologic malignancies, and hypomethylating agents are commonly used to treat myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). In these diseases, bone marrow mesenchymal stromal cells (MSCs) play a key supportive role through the production of various signals and interactions. The DNA methylation status of MSCs, likely to reflect their functionality, might be relevant to understand their contribution to the pathophysiology of these diseases. Consequently, the aim of our study was to analyze the modifications of DNA methylation profiles of MSCs induced by MDS or AML. MSCs from MDS/AML patients were characterized via 5-methylcytosine quantification, gene expression profiles of key regulators of DNA methylation, identification of differentially methylated regions (DMRs) by methylome array, and quantification of DMR-coupled genes expression. MDS and AML-MSCs displayed global hypomethylation and under-expression of DNMT1 and UHRF1. Methylome analysis revealed aberrant methylation profiles in all MDS and in a subgroup of AML-MSCs. This aberrant methylation was preferentially found in the sequence of homeobox genes, especially from the HOX family (HOXA1, HOXA4, HOXA5, HOXA9, HOXA10, HOXA11, HOXB5, HOXC4, and HOXC6), and impacted on their expression. These results highlight modifications of DNA methylation in MDS/AML-MSCs, both at global and focal levels dysregulating the expression of HOX genes well known for their involvement in leukemogenesis. Such DNA methylation in MSCs could be the consequence of the malignant disease or could participate in its development through defective functionality or exosomal transfer of HOX transcription factors from MSCs to hematopoietic cells.

The aim of this study was to assess the potential impact of the kinetics of serum levels of seven cytokines during induction in acute myeloid leukemia (AML) patients. Indeed, the role of cytokines, in the pathophysiology and response to therapy of AML patients, remains under investigation. Here, we report on the impact of peripheral levels of two cytokines, the Fms‐like tyrosine kinase 3 ligand (FL) and interleukin‐6 (IL‐6), evaluated during first‐line intensive induction. A new risk stratification can be proposed, which supersedes the ELN 2017 classification to predict survivals in AML patients by examining the kinetic profile of these cytokines during the induction phase. It segregates three groups of, respectively, high‐risk, characterized by a stagnation of low FL levels, intermediate risk, with dynamic increasing FL levels and high IL‐6 at day 22, and favorable risk with increasing FL levels but low IL‐6 at day 22., Here we report on the impact of the peripheral levels of two cytokines, the Fms‐like tyrosine kinase 3 ligand (FL), and interleukin‐6 (IL‐6), evaluated during first‐line intensive induction. Indeed, a new risk stratification can be proposed, which supersedes the ELN 2017 classification to predict survivals in AML patients by examining their profile during the induction phase.

The impact of acute graft versus host disease (GVHD) on survivals for patients receiving a haploidentical allogeneic stem-cell transplant (Allo-SCT) with peripheral blood stem-cells (PBSC) complemented by post-transplant cyclophosphamide (PTCY) is ill-known.This retrospective study included 131 patients who received a PBSC haplograft in order to precise the impact of acute GVHD on outcomes. There were 78 males and 53 females and the median age for the whole cohort was 59 years (range: 20-71). Thirty-five patients were allografted for a lymphoid disease and 96 for a myeloid malignancy, including 67 patients with acute myeloid leukemia (AML).The cumulative incidence (CI) of day 100 grade 2-4 and 3-4 acute GVHD was 43.4 + 4.6% and 16.7 + 3.4%, respectively. The 2-year CI of moderate/severe chronic GVHD was 10.1 + 2.8%. The only factor affecting the occurrence of GVHD was GVHD prophylaxis. Indeed, CI of day 100 grade 2-4 (but not grade 3-4) acute GVHD was significantly reduced when adding anti-thymoglobulin (ATG) to PTCY. However, in multivariate analysis, grade 2 acute GVHD was significantly associated with better disease-free (HR: 0.36; 95%CI: 0.19-0.69,Acute grade 2 GVHD is a factor of good prognosis after PBSC haplotransplant with PTCY. Further and larger studies are needed to clarify the complex question of GVHD prophylaxis in the setting of haplo-transplant, especially that of combining ATG and PTCY.

Low reactive oxygen species (ROS) levels are well-established characteristics of mouse hematopoietic stem cells (HSCs). However, little is known about these levels in human HSCs. This study aimed at quantifying ROS levels in human CD34+ CD38low and CD34+ CD38high human progenitors from bone marrow, cord blood and cells mobilized for autologous HSC transplantation. A specifically devised multiparameter flow cytometry method was used to quantify ROS levels (H2 DCFDA staining) in sub-populations of primary cells. Results were confirmed by assessing gene expression level of the ROS scavenger GPX3, a key determinant of HSC self-renewal, in sorted CD34+ CD38low and CD34+ CD38high cells. CD34+ CD38low cells from bone marrow and cord blood displayed significantly lower levels of ROS than CD34+ CD38high cells and other leukocytes. Moreover, the correlation between ROS and GPX3 expression was verified in sorted CD34+ CD38low and CD34+ CD38high cells. These results confirm, in human, data previously reported in mice. Moreover, the flow cytometry assay we developed could allow for a more precise enumeration of repopulating primitive progenitors in the course of HSC transplantation.

Allogeneic stem cell transplantation (allo-SCT) represents the most beneficial treatment for patients with active relapsed/refractory (R/R) hematologic malignancies. Recently, sequential regimens combining debulking chemotherapy followed by reduced-intensity conditioning (RIC) have shown encouraging results for these patients. In this retrospective study, we report the extended results of a sequential regimen of clofarabine, cytosine arabinoside, and RIC in 131 adults with active R/R myeloid disease at transplant. Conditioning consisted of clofarabine (30 mg/m2/day) and cytosine arabinoside (1 g/m2/day) for 5 days, followed, after a rest of 3 days, by an RIC combining cyclophosphamide (60 mg/kg) for 1 day, iv busulfan (3.2 mg/kg/day) for 2 days, and anti-thymocyte globulin (2.5 mg/kg/day) for 2 days. Between 2007 and 2016, 131 patients (males n = 75, median age: 52.6 years) were identified from the SFGM-TC registry. There were 111 acute myeloid leukemia (AML) patients and 20 cases with myelodysplastic or myeloproliferative syndrome. Status at transplant was known for all but 4 patients and was primary refractory (n = 81) and 1st or 2nd relapse (n = 46). All patients received allo-SCT from a matched donor (sibling n = 64, unrelated n = 67). Engraftment was observed in 105/122 (86%) evaluable cases and 63% of the patients achieved complete remission (CR) after transplant. The 1-year overall survival, disease-free survival, relapse incidence, non-relapse mortality, and graft-versus-host disease-free/relapse-free survival were 39.2%, 28.1%, 41.0%, 30.8%, and 22.2%, respectively. This study confirms that this sequential clofarabine-based regimen provides a high CR rate in this critical population, although relapse remains a matter of concern.

Inherited platelet function disorders are rare hemorrhagic diseases. The gold standard for their exploration is optical aggregometry; however, investigations by flow cytometry (FCM) are being increasingly used. In this review, the physiology of platelets is first recalled, setting the stage for the compartments of platelets that can be apprehended by specific and appropriate labeling. As this requires some pre-analytical precautions and specific analytical settings, a second part focuses on these characteristic aspects, based on literature and on the authors' experience in the field, for qualitative or quantitative explorations. Membrane labeling with antibodies to CD42a or CD41, respectively, useful to assess the genetic-related defects of Glanzmann thrombocytopenia and Bernard Soulier syndrome are then described. Platelet degranulation disorders are detailed in the next section, as they can be explored, upon platelet activation, by measuring the expression of surface P-Selectin (CD62P) or CD63. Mepacrin uptake and release after activation is another test allowing to explore the function of dense granules. Finally, the flip-flop anomaly related to Scott syndrome is depicted. Tables summarizing possible FCM assays, and characteristic histograms are provided as reference for flow laboratories interested in developing platelet exploration.

The influence of peripheral blood stem cell (PBSC) graft cell contents after transplant with post-transplant cyclophosphamide (PTCY) remains unclear. Here, we retrospectively report on a cohort of 77 adults who received a Baltimore-based reduced-intensity conditioning regimen either with fludarabine (n = 40) or clofarabine (n = 37) and PTCY. With a median follow-up of 29.2 months, [2-]year overall (OS), disease-free (DFS), and GVHD/relapse-free survival (GRFS) rates were 62.8%, 51%, and 36.7%, respectively. The incidence of grades [2–]4 acute GVHD was significantly higher in patients transplanted with a haplodonor (n = 56), at 57.1% vs 19% (p = 0.006). PBSC graft cell contents (CD45+, CD34+, and CD3+ cells) had no impact on any outcome. Considering immune reconstitution until 1 year, only monocytes were above the normal range (as early as day + 30) during the first year post-transplant. In multivariate analysis, an older donor (> 45 years) and a high/very high disease risk index were independently associated with lower OS. A higher monocyte count (> median) at day + 90 was also associated with better OS, DFS, and GRFS. Donor/recipient CMV status matching was independently associated with GRFS. In conclusion, our data support the fact that there is no need to manipulate the graft before infusion in the particular context of PBSC/PTCY Baltimore-based allotransplant.

Proper management of chronic lymphocytic leukemia (CLL) patients requiring therapy relies on two important prognostic and theranostic molecular features: respectively, the mutational status of tumoral cells immunoglobulin heavy chain variable domain (IGHV) and the characteristics of TP53. Both these (immuno)genetic analyses require multiple time-consuming amplification and sequencing techniques by Sanger or HTS. The capture-HTS technology, allowing to select regions of interest, represents an attractive alternative and has already been applied for the detection of clonality in lymphoproliferative disorders. Here, a single-step capture design was developed to concomitantly investigate for IGHV and TP53. This was applied to a training retrospective (n=14) and a validation prospective (n=91) cohorts of CLL patients. The training cohort demonstrated the robustness of the method by comparison with the classical Sanger sequencing technology (100% identical results) for the IGHV mutational status. This consistency was confirmed for the first 59 patients of the validation cohort. Overall, the IGHV status of whole population (n=103) was accurately identified. Simultaneously, deletion or mutations of TP53 were identified from the same capture-library and HTS-sequencing run for each patient. This novel approach provides, in a single assay, useful answers about the molecular landscape of CLL patients, allowing for a documented choice of therapy.Graphical abstract

International audience; The impact of pre-transplant anti-severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine in 20 recipients of allogeneic hematopoietic stem cell transplantation (Allo-HSCT) and/or their donors is reported here, showing that the persistence of anti-SARS-CoV-2 antibodies can be detected in almost all patients, whatever the type of vaccine used, and up to 9 months post transplant. Also, an anti-SARS-CoV-2 spike glycoprotein CD3+ T-cell response could be detected in six (35%) of 17 evaluable patients. This study provides a rationale to consider anti-SARS-CoV-2 vaccination of both recipients and donors before Allo-HSCT.

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT), proposed to patients with high-risk myeloid malignancies, may ultimately fail because of disease relapse. Bone marrow (BM) CD34

Current guidelines recommend flow cytometric analysis as part of the diagnostic assessment of patients with cytopenia suspected for myelodysplastic syndrome. Herein we describe the complete work-up of six cases using multimodal integrated diagnostics. Flow cytometry assessments are illustrated by plots from conventional and more recent analysis tools. The cases demonstrate the added value of flow cytometry in case of hypocellular, poor quality, or ambiguous bone marrow cytomorphology. Moreover, they demonstrate how immunophenotyping results support clinical decision-making in inconclusive and clinically 'difficult' cases.

Recent advances in the small field of the rare mixed phenotype acute leukemias (MPAL) are presented focusing on a better understanding of their pathophysiology and search for better therapeutic approaches.Three aspects of respective classification, therapy, and immunophenotype of MPAL are reviewed. New proposals have been made to segregate MPAL subtypes based on their genomic landscape. In parallel, it was found that a large array of therapeutic approaches has been tested in the past few years with increasingly good results. Finally, we explored the use of unsupervised flow cytometry analysis to dissect subtle variations in markers expression to better characterize the variegating aspect of MPALs. Genomic and immunophenotypic aspects more clearly link MPAL subtypes with bona fide acute myeloblastic of lymphoblastic leukemias. This is likely to impact therapeutic strategies, towards a better management and outcome.

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.

Simple Summary Pesticide exposure is a public health concern. Two recent studies reported that exposure of normal primary bone marrow mesenchymal stem/stromal cells (BM-MSCs) to low-dose pesticide mixture induces deleterious consequences, such as oxidative stress, senescence, accelerated aging and increased sensitivity to oncogenic hits. Here, we show that exposure to this mixture decreases aldehyde dehydrogenase-2 (ALDH2) activity, with a concomitant increase in acetaldehyde level and DNA damage and alters the MSC capacity to support primitive hematopoiesis. Similar abnormalities were observed in bone marrow-MSCs from patients suffering from myelodysplastic syndrome (MDS), suggesting a role of pesticide-induced ALDH2 inhibition in the pathophysiology of this pre-leukemic disease. Abstract (1) Background: The impact of occupational exposure to high doses of pesticides on hematologic disorders is widely studied. Yet, lifelong exposure to low doses of pesticides, and more particularly their cocktail effect, although poorly known, could also participate to the development of such hematological diseases as myelodysplastic syndrome (MDS) in elderly patients. (2) Methods: In this study, a cocktail of seven pesticides frequently present in water and food (maneb, mancozeb, iprodione, imazalil, chlorpyrifos ethyl, diazinon and dimethoate), as determined by the European Food Safety Authority, were selected. Their in vitro effects at low-doses on primary BM-MSCs from healthy volunteers were examined. (3) Results: Exposure of normal BM-MSCs to pesticides for 21 days inhibited cell proliferation and promoted DNA damage and senescence. Concomitantly, these cells presented a decrease in aldehyde dehydrogenase 2 (ALDH2: mRNA, protein and enzymatic activity) and an increase in acetaldehyde levels. Pharmacological inhibition of ALDH2 with disulfiram recapitulated the alterations induced by exposure to low doses of pesticides. Moreover, BM-MSCs capacity to support primitive hematopoiesis was significantly altered. Similar biological abnormalities were found in primary BM-MSCs derived from MDS patients. (4) Conclusions: these results suggest that ALDH2 could participate in the pathophysiology of MDS in elderly people long exposed to low doses of pesticides.