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Mast cell leukemia (MCL) is a rare subtype of systemic mastocytosis defined by ≥20% mast cells (MC) on a bone marrow aspirate. We evaluated 92 patients with MCL from the European Competence Network on Mastocytosis registry. Thirty-one (34%) patients had a diagnosis of MCL with an associated hematologic neoplasm (MCL-AHN). Chronic MCL (lack of C-findings) comprised 14% of patients, and only 4.5% had "leukemic MCL" (≥10% circulating MCs). KIT D816V was found in 62/85 (73%) evaluable patients; 9 (11%) individuals exhibited alternative KIT mutations, and no KIT variants were detected in 14 (17%) subjects. Ten evaluable patients (17%) had an abnormal karyotype and the poor-risk SRSF2, ASXL1, and RUNX1 (S/A/R) mutations were identified in 16/36 (44%) patients who underwent next-generation sequencing. Midostaurin was the most common therapy administered to 65% of patients and 45% as first-line therapy. The median overall survival (OS) was 1.6 years. In multivariate analysis (S/A/R mutations excluded owing to low event rates), a diagnosis of MCL-AHN (hazard ratio [HR], 4.7; 95% confidence interval [CI], 1.7-13.0; P = .001) and abnormal karyotype (HR, 5.6; 95% CI, 1.4-13.3; P = .02) were associated with inferior OS; KIT D816V positivity (HR, 0.33; 95% CI, 0.11-0.98; P = .04) and midostaurin treatment (HR, 0.32; 95% CI, 0.08-0.72; P = .008) were associated with superior OS. These data provide the most comprehensive snapshot of the clinicopathologic, molecular, and treatment landscape of MCL to date, and should help further inform subtyping and prognostication of MCL. ispartof: BLOOD ADVANCES vol:7 issue:9 pages:1713-1724 ispartof: location:United States status: published

SF3B1K700E is the most frequent mutation in myelodysplastic syndrome (MDS), but the mechanisms by which it drives MDS pathogenesis remain unclear. We derived a panel of 18 genetically matched SF3B1K700E- and SF3B1WT-induced pluripotent stem cell (iPSC) lines from patients with MDS with ring sideroblasts (MDS-RS) harboring isolated SF3B1K700E mutations and performed RNA and ATAC sequencing in purified CD34+/CD45+ hematopoietic stem/progenitor cells (HSPCs) derived from them. We developed a novel computational framework integrating splicing with transcript usage and gene expression analyses and derived a SF3B1K700E splicing signature consisting of 59 splicing events linked to 34 genes, which associates with the SF3B1 mutational status of primary MDS patient cells. The chromatin landscape of SF3B1K700E HSPCs showed increased priming toward the megakaryocyte- erythroid lineage. Transcription factor motifs enriched in chromatin regions more accessible in SF3B1K700E cells included, unexpectedly, motifs of the TEA domain (TEAD) transcription factor family. TEAD expression and transcriptional activity were upregulated in SF3B1-mutant iPSC-HSPCs, in support of a Hippo pathway-independent role of TEAD as a potential novel transcriptional regulator of SF3B1K700E cells. This study provides a comprehensive characterization of the transcriptional and chromatin landscape of SF3B1K700E HSPCs and nominates novel mis-spliced genes and transcriptional programs with putative roles in MDS-RS disease biology.

Myelodysplastic syndromes/neoplasms (MDS) are associated with variable clinical presentations and outcomes. The initial response criteria developed by the International Working Group (IWG) in 2000 have been used in clinical practice, clinical trials, regulatory reviews, and drug labels. While the IWG criteria were revised in 2006 and 2018 (the latter focusing on lower-risk disease), limitations persist in their application to higher-risk MDS and in their ability to fully capture clinical benefits of novel investigational drugs or to serve as valid surrogates for longer-term clinical endpoints (e.g., overall survival). Further, issues related to ambiguity and practicality of some criteria lead to variability in interpretation and inter-observer inconsistency in reporting results from the same sets of data. Thus, we convened an international panel of 36 MDS experts and used an established modified Delphi process to develop consensus recommendations for updated response criteria that would be more reflective of patient-centered and clinically relevant outcomes in higher-risk MDS. Among others, the IWG 2023 criteria include changes in the hemoglobin threshold for complete remission (CR), the introduction of CR with limited count recovery (CRL) and CR with partial hematologic recovery (CRh) as provisional response criteria, elimination of marrow CR, and specific recommendations for standardization of time-to-event endpoints and the derivation and reporting of responses. The updated criteria should lead to better correlation between patient-centered outcomes and clinical trial results in an era of multiple emerging new agents with novel mechanisms of action.

Contains fulltext : 290857.pdf (Publisher’s version ) (Closed access) Information on causes of death (CoDs) and the impact of myelodysplastic syndromes (MDS) on survival in patients with lower-risk MDS (LR-MDS) is limited. A better understanding of the relationship between disease characteristics, clinical interventions and CoDs may improve outcomes of patients with LR-MDS. We prospectively collected data on patients with LR-MDS in the European MDS registry from 2008 to 2019. Clinical, laboratory and CoDs data were obtained. To examine MDS-specific survival, relative survival (RS) was estimated using national life tables. Of 2396 evaluated subjects, 900 died (median overall survival [OS]: 4.7 years; median follow-up: 3.5 years). The most common CoDs were acute myeloid leukaemia/MDS (20.1%), infection (17.8%) and cardiovascular disease (CVD; 9.8%). Patients with isolated del(5q) and with red cell transfusion needed during the disease course, had a higher risk of fatal CVD. The 5-year OS was 47.3% and the 5-year RS was 59.6%, indicating that most patients died due to their underlying MDS. Older patients (aged >80 years) and the lowest-risk patients were more likely to die from competing causes. This study shows that MDS and its related complications play crucial role in the outcome of patients with LR-MDS. 01 februari 2023

Germ line DDX41 variants have been implicated in late-onset myeloid neoplasms (MNs). Despite an increasing number of publications, many important features of DDX41-mutated MNs remain to be elucidated. Here we performed a comprehensive characterization of DDX41-mutated MNs, enrolling a total of 346 patients with DDX41 pathogenic/likely-pathogenic (P/LP) germ line variants and/or somatic mutations from 9082 MN patients, together with 525 first-degree relatives of DDX41-mutated and wild-type (WT) patients. P/LP DDX41 germ line variants explained ∼80% of known germ line predisposition to MNs in adults. These risk variants were 10-fold more enriched in Japanese MN cases (n = 4461) compared with the general population of Japan (n = 20 238). This enrichment of DDX41 risk alleles was much more prominent in male than female (20.7 vs 5.0). P/LP DDX41 variants conferred a large risk of developing MNs, which was negligible until 40 years of age but rapidly increased to 49% by 90 years of age. Patients with myelodysplastic syndromes (MDS) along with a DDX41-mutation rapidly progressed to acute myeloid leukemia (AML), which was however, confined to those having truncating variants. Comutation patterns at diagnosis and at progression to AML were substantially different between DDX41-mutated and WT cases, in which none of the comutations affected clinical outcomes. Even TP53 mutations made no exceptions and their dismal effect, including multihit allelic status, on survival was almost completely mitigated by the presence of DDX41 mutations. Finally, outcomes were not affected by the conventional risk stratifications including the revised/molecular International Prognostic Scoring System. Our findings establish that MDS with DDX41-mutation defines a unique subtype of MNs that is distinct from other MNs.

The incidence and prognosis of clonal hematopoiesis in patients with isolated neutropenia among patients with idiopathic cytopenia of undetermined significance (ICUS), known as ICUS-N or chronic idiopathic neutropenia (CIN) patients, is poorly defined. The current study sought to investigate the frequency and clinical significance of mutations of genes implicated in myeloid malignancies using next-generation sequencing in patients with CIN (n = 185) with a long follow-up. We found that 21 (11.35%) of 185 patients carried a total of 25 somatic mutations in 6 genes with a median variant allele frequency of 12.75%. The most frequently mutated genes were DNMT3A and TET2 involving >80% of patients, followed by IDH1/2, SRSF2, and ZRSR2. The frequency of transformation to a myeloid malignancy was low in the total group of patients (5 of 185 patients [2.70%]). However, from the transformed patients, 4 belonged to the clonal group (4 of 21 [19.05%]) and 1 to the nonclonal group (1 of 164 [0.61%]), indicating that the presence of mutation(s) confers a relative risk for transformation of 31.24 (P = .0017). The variant allele frequency of the mutant clones in the transformed patients was >10% in all cases, and the genes most frequently associated with malignant transformation were SRSF2 and IDH1. No significant differences were identified between the clonal and nonclonal groups in the severity of neutropenia. Patients with clonal disease were older compared with nonclonal patients. These data contribute to the better understanding of the heterogeneous entities underlying ICUS and highlight the importance of mutation analysis for the diagnosis and prognosis of patients with unexplained neutropenias.

The classification of myeloid neoplasms and acute leukemias was last updated in 2016 within a collaboration between the World Health Organization (WHO), the Society for Hematopathology, and the European Association for Haematopathology. This collaboration was primarily based on input from a clinical advisory committees (CACs) composed of pathologists, hematologists, oncologists, geneticists, and bioinformaticians from around the world. The recent advances in our understanding of the biology of hematologic malignancies, the experience with the use of the 2016 WHO classification in clinical practice, and the results of clinical trials have indicated the need for further revising and updating the classification. As a continuation of this CAC-based process, the authors, a group with expertise in the clinical, pathologic, and genetic aspects of these disorders, developed the International Consensus Classification (ICC) of myeloid neoplasms and acute leukemias. Using a multiparameter approach, the main objective of the consensus process was the definition of real disease entities, including the introduction of new entities and refined criteria for existing diagnostic categories, based on accumulated data. The ICC is aimed at facilitating diagnosis and prognostication of these neoplasms, improving treatment of affected patients, and allowing the design of innovative clinical trials.

Myeloid neoplasms and acute leukemias derive from the clonal expansion of hematopoietic cells driven by somatic gene mutations. Although assessment of morphology plays a crucial role in the diagnostic evaluation of patients with these malignancies, genomic characterization has become increasingly important for accurate diagnosis, risk assessment, and therapeutic decision making. Conventional cytogenetics, a comprehensive and unbiased method for assessing chromosomal abnormalities, has been the mainstay of genomic testing over the past several decades and remains relevant today. However, more recent advances in sequencing technology have increased our ability to detect somatic mutations through the use of targeted gene panels, whole-exome sequencing, whole-genome sequencing, and whole-transcriptome sequencing or RNA sequencing. In patients with myeloid neoplasms, whole-genome sequencing represents a potential replacement for both conventional cytogenetic and sequencing approaches, providing rapid and accurate comprehensive genomic profiling. DNA sequencing methods are used not only for detecting somatically acquired gene mutations but also for identifying germline gene mutations associated with inherited predisposition to hematologic neoplasms. The 2022 International Consensus Classification of myeloid neoplasms and acute leukemias makes extensive use of genomic data. The aim of this report is to help physicians and laboratorians implement genomic testing for diagnosis, risk stratification, and clinical decision making and illustrates the potential of genomic profiling for enabling personalized medicine in patients with hematologic neoplasms.

Monocytosis may occur in numerous inflammatory conditions but is also the defining feature of chronic myelomonocytic leukemia (CMML). Clonal somatic mutations detectable in CMML may occur with aging in otherwise healthy individuals, so-called “clonal hematopoiesis” (CH). We investigated whether the combination of CH and monocytosis would represent an early developmental stage of CMML. We studied community-dwelling individuals with monocytosis (≥1 × 109/L and ≥10% of leukocytes) in the population-based Lifelines cohort (n = 144 676 adults). The prevalence and spectrum of CH were evaluated for individuals ≥60 years with monocytosis (n = 167 [0.8%]), and control subjects 1:3 matched for age and sex (n = 501). Diagnoses of hematological malignancies were retrieved by linkage to the Netherlands Cancer Registry (NCR). Monocyte counts and the prevalence of monocytosis increased with advancing age. Older individuals with monocytosis more frequently carried CH (50.9% vs 35.5%; P < .001). Monocytosis is associated with enrichment of multiple gene mutations (P = .006) and spliceosome mutations (P = .007) but not isolated mutated DNMT3A, TET2, or ASXL1. Persistent monocytosis over 4 years was observed in 30/102 evaluable individuals and associated with a higher prevalence of CH (63%). Myeloid malignancies, including 1 case of CMML, developed in 4 individuals with monocytosis who all carried CH. In conclusion, monocytosis and CH both occur at an older age and do not necessarily reflect clonal monocytic proliferation. In a fraction of older subjects with monocytosis, CH might constitute early clonal dominance in developing malignant myelomonocytic disease. Mutational spectra deviating from age-related CH require attention.

Somatic mutations in splicing factor genes frequently occur in myeloid neoplasms. While SF3B1 mutations are associated with myelodysplastic syndromes (MDS) with ring sideroblasts, SRSF2P95 mutations are found in different disease categories, including MDS, myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), and acute myeloid leukemia (AML). To identify molecular determinants of this phenotypic heterogeneity, we explored molecular and clinical features of a prospective cohort of 279 SRSF2P95-mutated cases selected from a population of 2663 patients with myeloid neoplasms. Median number of somatic mutations per subject was 3. Multivariate regression analysis showed associations between co-mutated genes and clinical phenotype, including JAK2 or MPL with myelofibrosis (OR = 26.9); TET2 with monocytosis (OR = 5.2); RAS-pathway genes with leukocytosis (OR = 5.1); and STAG2, RUNX1, or IDH1/2 with blast phenotype (MDS or AML) (OR = 3.4, 1.9, and 2.1, respectively). Within patients with SRSF2-JAK2 co-mutation, JAK2 dominance was invariably associated with clinical feature of MPN, whereas SRSF2 mutation was dominant in MDS/MPN. Within patients with SRSF2-TET2 co-mutation, clinical expressivity of monocytosis was positively associated with co-mutated clone size. This study provides evidence that co-mutation pattern, clone size, and hierarchy concur to determine clinical phenotype, tracing relevant genotype-phenotype associations across disease entities and giving insight on unaccountable clinical heterogeneity within current WHO classification categories.

Anemia is a major and currently poorly understood clinical manifestation of hematopoietic aging. Upon aging, hematopoietic clones harboring acquired leukemia-associated mutations expand and become detectable, now referred to as clonal hematopoiesis (CH). To investigate the relationship between CH and anemia of the elderly, we explored the landscape and dynamics of CH in older individuals with anemia. From the prospective, population-based Lifelines cohort (n = 167 729), we selected all individuals at least 60 years old who have anemia according to World Health Organization criteria (n = 676) and 1:1 matched control participants. Peripheral blood of 1298 individuals was analyzed for acquired mutations at a variant allele frequency (VAF) of 1% or higher in 27 driver genes. To track clonal evolution over time, we included all available follow-up samples (n = 943). CH was more frequently detected in individuals with anemia (46.6%) compared with control individuals (39.1%; P = .007). Although no differences were observed regarding commonly detected DTA mutations (DNMT3A, TET2, ASXL1) in individuals with anemia compared with control individuals, other mutations were enriched in the anemia cohort, including TP53 and SF3B1. Unlike individuals with nutrient deficiency (P = .84), individuals with anemia of chronic inflammation and unexplained anemia revealed a higher prevalence of CH (P = .035 and P = .017, respectively) compared with their matched control individuals. Follow-up analyses revealed that clones may expand and decline, generally showing only a subtle increase in VAF (mean, 0.56%) over the course of 44 months, irrespective of the presence of anemia. Specific mutations were associated with different growth rates and propensities to acquire an additional hit. In contrast to smaller clones (

Clonal cytopenia of undetermined significance (CCUS) is associated with an increased risk of developing a myeloid neoplasm with myelodysplasia (MN). To identify the features of the mutant clone(s) that is associated with clinical phenotype and progression, we studied the following cohorts of individuals: 311 patients with idiopathic cytopenia of undetermined significance (ICUS), 532 community-dwelling individuals without hematologic phenotype (n = 355) or with unexplained anemia (n = 177), and 592 patients with overt MN. Ninety-two of 311 (30%) patients with ICUS carried a somatic genetic lesion that signaled CCUS. Clonal hematopoiesis (CH) was detected in 19.7% and 27.7% of nonanemic and anemic community-dwelling individuals, respectively. Different mutation patterns and variant allele frequencies (VAFs) (clone metrics parameters) were observed in the conditions studied. Recurrent mutation patterns exhibited different VAFs associated with marrow dysplasia (0.17-0.48), indicating variable clinical expressivity of mutant clones. Unsupervised clustering analysis based on mutation profiles identified 2 major clusters, characterized by isolated DNMT3A mutations (CH-like cluster) or combinatorial mutation patterns (MN-like cluster), and showing different overall survival (HR, 1.8). In patients with CCUS, the 2 clusters had different risk of progression to MN (HR, 2.7). Within the MN-like cluster, distinct subsets with different risk of progression to MN were identified based on clone metrics. These findings unveil marked variability in the clinical expressivity of myeloid driver genes and underline the limitations of morphologic dysplasia for clinical staging of mutant hematopoietic clones. Clone metrics appears to be critical for informing clinical decision-making in patients with clonal cytopenia.

Germline variants in RUNX1, GATA2 and DDX41 may confer a predisposition to hereditary haematopoietic malignancies (HHMs) such as MDS and AML yet have distinct age ranges of malignancy diagnosis and a highly variable overall risk for leukemogenesis. The increased awareness and identification of carriers of these germline variants, particularly before development of malignancy, has changed the way in which individuals and families need to be managed in the clinic. Individuals need lifelong monitoring and may also need modification to treatments when malignancy does develop, compared to sporadic counterparts. Gaps in understanding pre-malignant states in HHM syndromes have hampered efforts to design effective clinical surveillance regimes, provide personalized pre-emptive treatments, and appropriate counselling to patients.

In the current classification of the World Health Organization (WHO), bone marrow mastocytosis (BMM) is a provisional variant of indolent systemic mastocytosis (ISM) defined by bone marrow involvement and absence of skin lesions. However, no additional diagnostic criteria for BMM have been proposed. Within the registry dataset of the European Competence Network on Mastocytosis, we compared characteristics and outcomes of 390 patients with BMM and 1175 patients with typical ISM. BMM patients were significantly older, predominantly male, had lower tryptase and lower burden of neoplastic mast cells, and displayed a higher frequency of allergic reactions, mainly triggered by Hymenoptera, than patients with typical ISM. The estimated 10-year progression-free survival of BMM and typical ISM was 95.9% and 92.6%, respectively. In BMM patients defined by WHO-based criteria, the presence of one B-Finding and tryptase level ≥125 ng/mL were identified as risk factors for progression in multivariate analyses. BMM patients without any of these risk factors were found to have better progression-free survival (p < 0.05) and better overall survival (p < 0.05) than other ISM patients. These data support the proposal to define BMM as a separate SM variant characterized by SM criteria, absence of skin lesions, absence of B-Findings, and tryptase levels

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Tumor protein p53 (TP53) is the most frequently mutated gene in cancer1,2. In patients with myelodysplastic syndromes (MDS), TP53 mutations are associated with high-risk disease3,4, rapid transformation to acute myeloid leukemia (AML)5, resistance to conventional therapies6–8 and dismal outcomes9. Consistent with the tumor-suppressive role of TP53, patients harbor both mono- and biallelic mutations10. However, the biological and clinical implications of TP53 allelic state have not been fully investigated in MDS or any other cancer type. We analyzed 3,324 patients with MDS for TP53 mutations and allelic imbalances and delineated two subsets of patients with distinct phenotypes and outcomes. One-third of TP53-mutated patients had monoallelic mutations whereas two-thirds had multiple hits (multi-hit) consistent with biallelic targeting. Established associations with complex karyotype, few co-occurring mutations, high-risk presentation and poor outcomes were specific to multi-hit patients only. TP53 multi-hit state predicted risk of death and leukemic transformation independently of the Revised International Prognostic Scoring System (IPSS-R)11. Surprisingly, monoallelic patients did not differ from TP53 wild-type patients in outcomes and response to therapy. This study shows that consideration of TP53 allelic state is critical for diagnostic and prognostic precision in MDS as well as in future correlative studies of treatment response. Clinical sequencing across a large prospective cohort of patients with myelodysplasic syndrome uncovers distinct associations between the mono- and biallelic states of TP53 and clinical presentation

Purpose of review Clinical and experimental studies have uncovered relevant clinical implications of clonal hematopoiesis. However, the true magnitude of this process, clonal dynamics over time and mechanisms of progression into overt malignancy remain to be largely elucidated. In this article, the consequences of clonal hematopoiesis, its significance in the context of cytopenia, and its implications in the clinical management of patients with myeloid malignancies are reviewed and discussed. Recent findings Clonal hematopoiesis has been associated with higher risk of hematologic cancers, as well as of death from cardiovascular causes. Clonal hematopoiesis has been proven clinically relevant in the context of disorders characterized by peripheral blood cytopenia, including aplastic anemia, cytopenia of undetermined significance, as well as unexplained anemia of the elderly. Summary The available evidence has been proving the utility of somatic mutational analysis in patients with unexplained cytopenia, as well as in those receiving a diagnosis of myeloid neoplasm, enabling more accurate diagnosis, risk assessment, effective therapeutic strategies and residual disease monitoring. The access to a minimally invasive assessment is paving the way for screening programs of clonal hematopoiesis in individuals with absent or mild hematologic phenotype, as well as for therapeutic targeting of preleukemia cells.

In 2016, the European Hematology Association (EHA) published the EHA Roadmap for European Hematology Research1 aiming to highlight achievements in the diagnostics and treatment of blood disorders, and to better inform European policy makers and other stakeholders about the urgent clinical and scientific needs and priorities in the field of hematology. Each section was coordinated by 1-2 section editors who were leading international experts in the field. In the 5 years that have followed, advances in the field of hematology have been plentiful. As such, EHA is pleased to present an updated Research Roadmap, now including 11 sections, each of which will be published separately. The updated EHA Research Roadmap identifies the most urgent priorities in hematology research and clinical science, therefore supporting a more informed, focused, and ideally a more funded future for European hematology research. The 11 EHA Research Roadmap sections include Normal Hematopoiesis; Malignant Lymphoid Diseases; Malignant Myeloid Diseases; Anemias and Related Diseases; Platelet Disorders; Blood Coagulation and Hemostatic Disorders; Transfusion Medicine; Infections in Hematology; Hematopoietic Stem Cell Transplantation; CAR-T and Other Cell-based Immune Therapies; and Gene Therapy.

Background While histo- and cytomorphological examinations are central to the diagnosis of myelodysplastic syndromes (MDS), significant inter-observer variability exists. The diagnosis can be challenging in pancytopenic patients (pts) without evidence of dysplasia and is contingent on observer expertise. We developed and externally validated a geno-clinical model that uses mutational data and peripheral blood counts/clinical variables to distinguish MDS from other myeloid malignancies. Methods Clinical and genomic data, including commercially available next-generation sequencing panels, were obtained for patients (pts) treated at the Cleveland Clinic (CC; 652 pts), Munich Leukemia Laboratory (MLL; 1509 pts), and the University of Pavia in Italy (UP, 536 pts). All patients had carried a diagnosis of MDS, chronic myelomonocytic leukemia (CMML), MDS/myeloproliferative neoplasm overlap (MDS/MPN), myeloproliferative neoplasm (MPN; either polycythemia vera, essential thrombocythemia, or myelofibrosis), clonal cytopenia of undetermined significance (CCUS), or idiopathic cytopenia of undetermined significance (ICUS). All diagnoses were established with bone marrow aspiration and according to World Health Organization 2017 criteria. The training cohort included data from CC and UP and randomly divided into learner (80%) and test (20%) cohorts. The final model was independently validated in the MLL cohort. A machine learning algorithm was used to build the model; multiple extraction algorithms were used to extract genomic/clinical variables on both the cohort and individual levels. Performance was evaluated according to the area under the curve of the receiver operating characteristic (ROC-AUC) and accuracy matrices. Results Among the 2697 pts included from all sites, the median age was 70 years [36 - 86]. Median hemoglobin (Hb) was 10.4g/dl [6.9 - 15.7], median platelet count (PLT) was 132 k/dL [14 - 722], median WBC count was 5.3 k/dL [1.4 - 49.9], median ANC was 2.8 k/dL [0.3 - 27.7], median monocyte count was 0.3 k/dL [0 - 9.9], and median lymphocyte count (ALC) was 1.1 k/dL [0.1 - 5.4], and median peripheral blast percentage 0% [0 - 8]. The most commonly mutated genes in all patients were (list top 5 genes) and among pts with MDS were SF3B1 (27%), TET2 (25%), ASXL1 (19%), SRSF2 (16%), and DNMT3A (11%); among patients with MDS-MPN/CMML, the most commonly mutated genes were MDS-MPN/CMML (TET2 46%, ASXL1 34%, SRSF2 29%, RUNX1 13%, CBL 12%) ; among patients with MPNs, the most commonly mutated genes were (JAK2 64%, ASXL1 27%, TET2 14%, DNMT3A 8%, U2AF1 7%); among patients with CCUS the most commonly mutated genes were (TET2 41%, DNMT3A 27%, ASXL1 19%, SRSF2 17%, ZRSR2 10%). The most important features for model predictions (ranked from the most to the least important) included: number of mutations detected/sample, peripheral blast percentage, AMC, JAK2 status, Hb, basophil count, age, eosinophil count, ALC, WBC, EZH2 mutation status, ANC, mutation status of KRAS and SF3B1, platelets, and gender. The final model achieved an average AUROC of 0.95 (95% CI 0.93-0.96) when applied to the test cohort and 0.93 (95% CI 0.91 - 0.94) when it was applied to the MLL cohort. The model also provides individual-level explanations for predictions, providing top differential diagnoses and individual-level explanations of how features influence a putative diagnosis (Figure 1b). Conclusions We developed and externally validated a highly accurate and interpretable model that can distinguish MDS from other myeloid malignancies using clinical and mutational data from a large international cohort. The model can provide personalized interpretations of its outcome and can aid physicians and hematopathologists in recognizing MDS with high accuracy when encountering pts with pancytopenia and with a suspected diagnosis of MDS. Disclosures Sekeres: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda/Millenium: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mukherjee:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Partnership for Health Analytic Research, LLC (PHAR, LLC): Honoraria; Bristol Myers Squib: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Aplastic Anemia and MDS International Foundation: Honoraria; Celgene/Acceleron: Membership on an entity's Board of Directors or advisory committees; EUSA Pharma: Consultancy. Gerds:Sierra Oncology: Research Funding; Imago Biosciences: Research Funding; Apexx Oncology: Consultancy; Celgene: Consultancy, Research Funding; Incyte Corporation: Consultancy, Research Funding; Roche/Genentech: Research Funding; CTI Biopharma: Consultancy, Research Funding; AstraZeneca/MedImmune: Consultancy; Gilead Sciences: Research Funding; Pfizer: Research Funding. Maciejewski:Alexion, BMS: Speakers Bureau; Novartis, Roche: Consultancy, Honoraria. Nazha:Jazz: Research Funding; Incyte: Speakers Bureau; Novartis: Speakers Bureau; MEI: Other: Data monitoring Committee.

Myelodysplastic syndromes (MDSs) represent a heterogeneous group of hematological stem cell disorders with an increasing burden on health care systems. Evidence-based MDS guidelines and recommendations (G/Rs) are published but do not necessarily translate into better quality of care if adherence is not maintained in daily clinical practice. Guideline-based indicators (GBIs) are measurable elements for the standardized assessment of quality of care and, thus far, have not been developed for adult MDS patients. To this end, we screened relevant G/Rs published between 1999 and 2018 and aggregated all available information as candidate GBIs into a formalized handbook as the basis for the subsequent consensus rating procedure. An international multidisciplinary expert panel group (EPG) of acknowledged MDS experts (n = 17), health professionals (n = 7), and patient advocates (n = 5) was appointed. The EPG feedback rates for the first and second round were 82% (23 of 28) and 96% (26 of 27), respectively. A final set of 29 GBIs for the 3 domains of diagnosis (n = 14), therapy (n = 8), and provider/infrastructural characteristics (n = 7) achieved the predefined agreement score for selection (>70%). We identified shortcomings in standardization of patient-reported outcomes, toxicity, and geriatric assessments that need to be optimized in the future. Our GBIs represent the first comprehensive consensus on measurable elements addressing best practice performance, outcomes, and structural resources. They can be used as a standardized instrument with the goal of assessing, comparing, and fostering good quality of care within clinical development cycles in the daily care of adult MDS patients.

Diagnostic criteria for hypoplastic myelodysplasic syndrome (h-MDS) have not been clearly established, making the differential diagnosis from other bone marrow failure syndromes (BMF) challenging. In this study, we aimed to delineate clinical, histopathological, and molecular features of h-MDS, based on a large and well-annotated cohort of patients with bone marrow (BM) hypocellularity. The study included 534 consecutive adult patients with hypocellular BM (278 h-MDS and 136 aplastic anemia), and 727 with normo- or hypercellular MDS (n-MDS). Comparison of clinical features of patients with h-MDS as defined by BM cellularity ≤25% (n = 204) or reduced age-adjusted cellularity (n = 74) did not reveal significant differences. We developed a diagnostic score to discriminate h-MDS from non-malignant BMF based on histological and cytological variables with the highest specificity for MDS (h-score). The information from chromosomal abnormalities and somatic mutation patterns was then integrated into a cyto-histological/genetic score (hg-score). This score was able to segregate two groups of h-MDS with a significantly different risk of blast progression (P

Red blood cell transfusions (RBCT) remain the cornerstone of supportive care in lower-risk myelodysplastic syndrome (LRMDS) [1]. Transfusion dependency in LRMDS patients is associated with inferior outcomes, mainly attributed to severe bone marrow failure [2]. However, iron toxicity, due to frequent RBCT or ineffective erythropoiesis, may be an additional negative prognostic factor [3,4,5,6]. Recently, much progress has been made in unraveling the iron metabolism. The peptide hormone hepcidin is the key regulator by inhibiting iron uptake through degradation of ferroportin, a cellular iron exporter [7]. Erythroferrone and GDF15, produced by erythroblasts, inhibit hepcidin production, which leads to increased uptake and cellular release of iron for the purpose of erythropoiesis [8]. The pathophysiology of iron metabolism in MDS is still not completely understood. Exceedingly high reactive oxygen species (ROS) levels are associated with iron toxicity, disease development, and progression in MDS patients [9,10,11,12]. Malondialdehyde (MDA), resulting from lipid peroxidation of polyunsaturated fatty acids, is a biomarker of oxidative stress [10, 12]. Currently, little is known about the prognostic impact of ROS in MDS patients. The aim of this study is twofold: (1) describe iron and oxidative stress parameters over time in LRMDS patients and (2) to assess their effect on overall and progression-free survival. The EUMDS registry prospectively collects observational data on newly diagnosed LRMDS patients from 148 centers in 16 countries in Europe and Israel as of January 2008. All patients provided informed consent. Clinical data were collected at baseline and at each six-monthly follow-up visit. Serum samples were collected prospectively at each visit from 256 patients included in six participating countries. Conventional iron parameters were measured with routine assays. We additionally analyzed hepcidin, growth differentiation factor 15 (GDF15), soluble transferrin receptor (sTfR), non-transferrin bound iron (NTBI), labile plasma iron (LPI), and MDA. Subjects were prospectively followed until death, loss to follow-up, or withdrawal of consent. All iron parameters were measured centrally at the department of Laboratory Medicine of the Radboudumc, Nijmegen, The Netherlands. Serum samples were collected just prior to transfusion in transfusion-dependent patients and stored at −80 °C. Details on the assays and reference ranges of hepcidin, GDF15, sTfR, NTBI, LPI, and MDA are provided in the supplement. The Spearman rank test was used to evaluate correlations between iron parameters. We stratified the results by transfusion dependency per visit and the presence of ring sideroblasts. When evaluating temporal changes in iron parameters, with linear quantile mixed models, we excluded patients from the timepoint they received iron chelation therapy. Overall survival (OS) was defined as the time from MDS diagnosis to death or, in case of progression-free survival, to date of progression or death; patients still alive at the end of follow-up were censored. Time-dependent Kaplan–Meier curves and cox proportional hazards models were used. In total, 256 consecutive patients, were included in this study. Over five six-monthly visits, 1040 samples were collected. Table 1 describes the patient characteristics. Most patients without ring sideroblasts were transfusion-independent at diagnosis (nonRS-TI; 55.9%), 18.8% with ring sideroblasts were transfusion-independent (RS-TI), 18.4% without ring sideroblasts were transfusion-dependent (nonRS-TD), and 7% with ring sideroblasts were transfusion-dependent patients (RS-TD). The median follow-up time was 6.6 years (95% CI 5.9–7.0). LPI was positively correlated with transferrin saturation (TSAT) (r = 0.15, p < 0.001, Fig. S1). LPI values increased exponentially at TSAT values above 80%. This effect was most pronounced in the transfusion-dependent groups, but also observed in the RS-TI group. MDA was weakly correlated with NTBI (r = 0.09, p = 0.069) and negatively correlated with hemoglobin level (r = −0.1, p = 0.033). GDF15 and hepcidin were negatively correlated in the RS-TI and nonRS-TD group and significantly negatively correlated in the RS-TD group (r = −0.34, p = 0.007, Fig. S2). Serum ferritin levels were elevated in all subgroups with a mean value of 858 µg/L at visit 5. The highest serum ferritin levels were observed in the RS-TD group (mean value at visit 5: 2092 µg/L, Table S1). Serum ferritin increased significantly per visit in the RS-TD group (beta 454.46 µg/L; 95% CI 334.65–574.27), but not in the other groups (Table S2). All subgroups, except for the nonRS-TI, had elevated TSAT levels. TSAT levels were most markedly increased in the RS-TD group with a mean TSAT of 88% at visit 5 (Table S1). In both transfusion-dependent groups the median increase per visit was significant (Table S2). LPI was elevated in the RS-TD group exclusively with a mean value of 0.59 µmol/L at visit 5 (Table S1). NTBI was elevated in all subgroups, with the highest values in the RS-TD group (Table S1). The increase in median NTBI level was significant in both transfusion-dependent groups (Table S2). Hepcidin levels were markedly elevated in the nonRS-TD group. Interestingly, hepcidin levels were lower in the RS-TD group, probably reflecting ineffective erythropoiesis, likewise supported by lower hepcidin/ferritin ratios in RS groups (Table S1). Median hepcidin levels increased over time in the transfusion-dependent subgroups only (Table S2). GDF15 levels, analyzed in the light of its potential role in hepcidin suppression, were increased in all subgroups (Table S1). The RS subgroups had higher GDF15 levels compared to the nonRS groups, reflecting increased erythropoiesis. Mean sTfR levels were within the reference range in all subgroups except for the RS-TI group, which showed elevated levels, reflecting...

Germline pathogenic TERT variants are associated with short telomeres and an increased risk of developing myelodysplastic syndrome (MDS) among patients with a telomere biology disorder. We identified TERT rare variants in 41 of 1514 MDS patients (2.7%) without a clinical diagnosis of a telomere biology disorder who underwent allogeneic transplantation. Patients with a TERT rare variant had shorter telomere length (P < .001) and younger age at MDS diagnosis (52 vs 59 years, P = .03) than patients without a TERT rare variant. In multivariable models, TERT rare variants were associated with inferior overall survival (P = .034) driven by an increased incidence of nonrelapse mortality (NRM; P = .015). Death from a noninfectious pulmonary cause was more frequent among patients with a TERT rare variant. Most variants were missense substitutions and classified as variants of unknown significance. Therefore, we cloned all rare missense variants and quantified their impact on telomere elongation in a cell-based assay. We found that 90% of TERT rare variants had severe or intermediate impairment in their capacity to elongate telomeres. Using a homology model of human TERT bound to the shelterin protein TPP1, we inferred that TERT rare variants disrupt domain-specific functions, including catalysis, protein–RNA interactions, and recruitment to telomeres. Our results indicate that the contribution of TERT rare variants to MDS pathogenesis and NRM risk is underrecognized. Routine screening for TERT rare variants in MDS patients regardless of age or clinical suspicion may identify clinically inapparent telomere biology disorders and improve transplant outcomes through risk-adapted approaches.

Theranostics 11(1), 292-303 (2021). doi:10.7150/thno.51872, Published by Ivyspring, Wyoming, NSW

Peripheral blood cytopenias may precede the development of hematological malignancies and frequently pose clinical challenges in the older population. The natural course of (mild) cytopenias during aging and their association with hematological disorders in community-dwelling individuals are not well studied. Within the population-based Lifelines cohort (n = 167729), we studied changes in peripheral blood counts, occurrence of cytopenias, and associated hematological outcomes in the context of aging. Development of hematological malignancies and (cause-specific) mortality were evaluated by linkage to nationwide registries. Anemia and thrombocytopenia emerged with older age, in line with a general age-related decline in these blood counts. For neutropenia, no increase in prevalence with older age was observed. Using standard reference limits to define cytopenias, anemia (hazard ratio [HR], 1.84; 95% confidence interval [CI], 1.59-2.12), thrombocytopenia (HR, 1.58; 95% CI, 1.32-1.89), and, especially the concomitant presence of anemia and thrombocytopenia (HR, 4.75; 95% CI, 2.98-7.55) were associated with inferior overall survival. Only a minor proportion of deaths was explained by diagnosed hematological malignancies, with the majority attributable to other causes. Neutropenia, either isolated (HR, 0.88; 95% CI, 0.73-1.06) or combined with another cytopenia, did not affect overall survival. For individuals aged ≥60 years, 5-year cumulative incidence of hematological malignancies was 0.60% (95% CI, 0.50-0.70), with higher incidences among those with anemia (P < .001) or thrombocytopenia (P < .001) but not neutropenia (P = .201). Highest cumulative incidences of diagnoses and mortality from hematological malignancies were observed in individuals with >1 cytopenia. We conclude that anemia and thrombocytopenia, but not neutropenia, are associated with inferior overall survival of community-dwelling individuals. Hematological malignancies develop in a small fraction of these cases.

Contains fulltext : 237720.pdf (Publisher’s version ) (Open Access) We present a noninvasive Web-based app to help exclude or diagnose myelodysplastic syndrome (MDS), a bone marrow (BM) disorder with cytopenias and leukemic risk, diagnosed by BM examination. A sample of 502 MDS patients from the European MDS (EUMDS) registry (n > 2600) was combined with 502 controls (all BM proven). Gradient-boosted models (GBMs) were used to predict/exclude MDS using demographic, clinical, and laboratory variables. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were used to evaluate the models, and performance was validated using 100 times fivefold cross-validation. Model stability was assessed by repeating its fit using different randomly chosen groups of 502 EUMDS cases. AUC was 0.96 (95% confidence interval, 0.95-0.97). MDS is predicted/excluded accurately in 86% of patients with unexplained anemia. A GBM score (range, 0-1) of less than 0.68 (GBM < 0.68) resulted in a negative predictive value of 0.94, that is, MDS was excluded. GBM ≥ 0.82 provided a positive predictive value of 0.88, that is, MDS. The diagnosis of the remaining patients (0.68 ≤ GBM < 0.82) is indeterminate. The discriminating variables: age, sex, hemoglobin, white blood cells, platelets, mean corpuscular volume, neutrophils, monocytes, glucose, and creatinine. A Web-based app was developed; physicians could use it to exclude or predict MDS noninvasively in most patients without a BM examination. Future work will add peripheral blood cytogenetics/genetics, EUMDS-based prospective validation, and prognostication.

Available evidence suggests that in most patients with LR-MDS the risk of death is not related to disease progression but is mainly attributable to non-leukemic death. 2,17 In addition, a proportion of these patients have prolonged survival that precludes the design of clinical trials adopting OS as a primary endpoint. These challenges have resulted in potentially biased assessment of the effectiveness and appropriate use of the available interventions in this patient population. The EUMDS Registry has identified novel meaningful outcome indicators and clinical endpoints, and reliable measures of response to HCI (Figure 4). The results of our analysis indicate that RBCT density is strongly associated with a decreased OS, even at relatively low dose densities. In addition, we observed that an early decrease in platelet count is an independent adverse prognostic indicator in LR-MDS, and combining relative platelet drop and transfusion dependency allows early identification of patients at risk of rapid progression, and may guide early therapeutic interventions, including allogeneic hematopoietic stem cell transplantation or experimental interventions. Taken together, these results indicate that regular RBCT requirement, early platelet count kinetics, and restriction in HRQoL are early independent and meaningful outcome indicators, and reliable measures of effectiveness of therapeutic interventions, evaluated in this set of studies. These findings support the integration of RBCT requirement and HRQoL in the general core outcome sets and in response criteria in patients with LR-MDS, and have important implications for clinical practice and the design of clinical endpoints. Our results strongly support the adoption of freedom from transfusion as a meaningful clinical endpoint in patients with LR-MDS. Anemia is the main determinant of therapeutic intervention in patients with LR-MDS, and ESA are recommended as first-line treatment for patients with symptomatic anemia. 10 The observational studies within the EUMDS Registry showed that the response rate, as well as the capacity of these agents to delay the onset of a regular RBCT need, is most pronounced in RBCT-naïve patients. These results identified early initiation of treatment with ESA as a major treatment response indicator, and indicate that ESA should be recommended in LR-MDS patients with symptomatic anemia before starting regular RBCT. After the onset of RBCT dependency, patients with LR-MDS are prone to long-term accumulation of iron. 1,43 The EUMDS Registry studies provided evidence that elevated LPI levels are associated with reduced survival in RBCT dependent patients, whereas iron chelation therapy normalizes LPI levels. These findings suggest that NTBI and LPI may serve as early indicators of iron toxicity and a means to measure the effectiveness of iron chelation therapy in patients with LR-MDS. However, qualified NTBI and LPI are only currently available in specialized laboratories. 44 Large observational cohorts with detailed clinical and laboratory data, like the EUMDS cohort, are the ideal framework in which to identify well defined MDS subtypes that may benefit from novel targeted treatments. An example of such a subtype is MDS with loss of parts of chromosome 5, namely del5q; these patients have a relatively favorable outcome on lenalidomide treatment. In order to identify homogeneous subsets of patients within MDS, preliminary evidence has suggested that recently identified mutations in splicing factors may recognize distinct disease entities within myeloid neoplasms. 45 Splicing modulators are now in pre-clinical testing, and are very likely to lead to the introduction of effective drugs for specific groups of MDS patients. Luspatercept, a specific inhibitor of growth and differentiation factor-11, a member of the transforming growth factor β superfamily, induced substantial improvement of anemia, especially in patients with ring sideroblasts. 46 Characterization of individual cases by new genetic markers (one of the main objectives of the MDS-RIGHT project) will allow refined classification of patients into biological subgroups that are expected to respond differently to therapeutic interventions to guide discontinuation of those interventions that are less effective or less cost-effective. The main question is whether RCT data and retrospective cohort data in selected tertiary care centers are representative of the 'real world' data of the older patients with LR-MDS in the general population. A careful comparison of the 'real world' data and the RCT data will be needed in order to provide a clear answer to these questions. Meanwhile, the current analyses of data collected over 10 years in the EUMDS Registry provides relevant and important information which could help assess prognosis and response to standard interventions in this older patient group.

The 2016 revision of the World Health Organization classification of tumors of hematopoietic and lymphoid tissues is characterized by a closer integration of morphology and molecular genetics. Notwithstanding, the myelodysplastic syndrome (MDS) with isolated del(5q) remains so far the only MDS subtype defined by a genetic abnormality. Approximately half of MDS patients carry somatic mutations in spliceosome genes, with SF3B1 being the most commonly mutated one. SF3B1 mutation identifies a condition characterized by ring sideroblasts (RS), ineffective erythropoiesis, and indolent clinical course. A large body of evidence supports recognition of SF3B1-mutant MDS as a distinct nosologic entity. To further validate this notion, we interrogated the data set of the International Working Group for the Prognosis of MDS (IWG-PM). Based on the findings of our analyses, we propose the following diagnostic criteria for SF3B1-mutant MDS: (1) cytopenia as defined by standard hematologic values, (2) somatic SF3B1 mutation, (3) morphologic dysplasia (with or without RS), and (4) bone marrow blasts

Iron overload due to red blood cell transfusions is associated with morbidity and mortality in lower-risk myelodysplastic syndrome patients. Many studies suggested improved survival after iron chelation therapy, but valid data are limited. The aim of this study was to assess the effect of iron chelation on overall survival and hematological improvement in lower-risk myelodysplastic syndrome patients in the European MDS registry. We compared chelated patients with a contemporary, non-chelated control group within the European MDS registry, that met the eligibility criteria for starting iron chelation. A Cox proportional hazards model was used to assess overall survival, treating receipt of chelation as a time-varying variable. Additionally, chelated and non-chelated patients were compared using a propensity-score matched model. Of 2200 patients, 224 received iron chelation. The hazard ratio and 95% confidence interval for overall survival for chelated patients, adjusted for age, sex, comorbidity, performance status, cumulative red blood cell transfusions, IPSS-R, and presence of ringed sideroblasts was 0.50 (0.34-0.74). The propensity-score analysis, matched for age, sex, country, red blood cell transfusion intensity, ferritin level, comorbidity, performance status, and IPSS-R and additionally corrected for cumulative red blood cell transfusions and presence of ringed sideroblasts, demonstrated a significantly improved overall survival for chelated patients with a hazard ratio of 0.42 (0.27-0.63) compared to non-chelated patients. Up to 39% of chelated patients reached an erythroid response. In conclusion, our results suggest that iron chelation may improve overall survival and hematopoiesis in transfused lower-risk myelodysplastic syndrome patients. This trial was registered at www.clinicaltrials.gov as #NCT00600860.

SF3B1, SRSF2, and U2AF1 are the most frequently mutated splicing factor genes in the myelodysplastic syndromes (MDS). We have performed a comprehensive and systematic analysis to determine the effect of these commonly mutated splicing factors on pre-mRNA splicing in the bone marrow stem/progenitor cells and in the erythroid and myeloid precursors in splicing factor mutant MDS. Using RNA-seq, we determined the aberrantly spliced genes and dysregulated pathways in CD34+ cells of 84 patients with MDS. Splicing factor mutations result in different alterations in splicing and largely affect different genes, but these converge in common dysregulated pathways and cellular processes, focused on RNA splicing, protein synthesis, and mitochondrial dysfunction, suggesting common mechanisms of action in MDS. Many of these dysregulated pathways and cellular processes can be linked to the known disease pathophysiology associated with splicing factor mutations in MDS, whereas several others have not been previously associated with MDS, such as sirtuin signaling. We identified aberrantly spliced events associated with clinical variables, and isoforms that independently predict survival in MDS and implicate dysregulation of focal adhesion and extracellular exosomes as drivers of poor survival. Aberrantly spliced genes and dysregulated pathways were identified in the MDS-affected lineages in splicing factor mutant MDS. Functional studies demonstrated that knockdown of the mitosis regulators SEPT2 and AKAP8, aberrantly spliced target genes of SF3B1 and SRSF2 mutations, respectively, led to impaired erythroid cell growth and differentiation. This study illuminates the effect of the common spliceosome mutations on the MDS phenotype and provides novel insights into disease pathophysiology.

Background. The classic Ph-negative myeloproliferative neoplasms (MPN) are a group of clonal haematopoietic disorders, including polycythemia vera (PV), essential thrombocythemia (ET) and myelofibrosis (MF), whose shared and diverse phenotypic signatures are caused by a dysregulated JAK/STAT signal transduction because of acquired somatic mutations. It has been demonstrated that autoimmune diseases and MPN can be associated (Kristinsson et al., Haematologica. 2010 Jul;95(7):1216-20.), suggesting a common background of immune dysregulation (Barosi, Curr Hematol Malig Rep. 2014 Dec;9(4):331-9). SARS-CoV-2 infection displays extreme inter-individual clinical variability, ranging from silent infection to lethal disease. It has been described that at least 10% of patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia have neutralizing autoantibodies (AAbs) against type I IFNs, that precede SARS-CoV-2 infection (Bastard et al., Science. 2020 Oct 23;370(6515):eabd4585). In this study we searched for AAbs against type I IFNs in a cohort of MPN patients to evaluate the prevalence of these AAbs in the MPN population and to check for clinical correlations, including severity of COVID-19. Methods. Plasma samples from consecutively referred MPN patients were prospectively collected between November 2020 and June 2021 and frozen at -30°C immediately after collection. Levels of AAbs against type I IFN subtypes including IFNs alpha, beta and omega were measured using the enzyme-linked immunosorbent assay (ELISA) and a neutralization assay, as previously reported (Bastard et al., Science. 2020 Oct 23;370(6515):eabd4585; Moreews et al., Sci Immunol. 2021 May 25;6(59):eabh1516). Results. We included a total of 219 MPN patients (101 ET, 76 PV, 36 MF and 6 MPN unclassificable). Neutralizing AAbs to type I IFNs were detected in 29 patients (13.2%, 95%CI: 9.1% - 18.5%). Comparing patients with and without AAbs we observed a significant difference in terms of distribution of MPN diagnosis (P = 0.029) and driver mutations (P = 0.019), while we did not observe a difference in terms of age, sex, and treatment (Table 1). Overall, 29 patients (13%) got SARS-CoV-2 infection and 8 of them (28%) required hospitalization due to severe COVID-19. AAbs against type I IFNs were detected in 4 of the 29 SARS-CoV-2 infected patients. A higher rate of hospitalization for severe COVID-19 was observed in patients with AAbs to type I IFNs (2 of 4 patients, 50%) compared to those without these AAbs (6 of 25 patients, 24%), although the difference did not reach a statistical significance (P = 0.300). Conclusions. In this study, we detected a prevalence of AAbs against type I IFNs which is much higher in our MPN cohort (13%) than in the general population (2-3%). We also found a correlation between the presence of AAbs to type I IFNs and both the hematological diagnosis and the driver mutation. Despite a comparable prevalence of SARS-CoV-2 infection between MPN patients with or without AAbs to type I IFNs, we observed a different rate of hospitalization due to severe COVID-19 which is almost twice in those with AAbs against type I IFNs compared to those without these AAbs. However, this difference did not reach a statistical significance, probably because of the low number of SARS-CoV-2 infection in the subgroup of patients with AAbs against type I IFNs. Thus, further studies to analyse the prevalence of AAbs against type I IFNs in patients with MPN, their association with other forms of auto-immunity and severe COVID-19 are warranted. Figure 1 Figure 1. Disclosures Arcaini: Gilead Sciences: Research Funding; Bayer, Celgene, Gilead Sciences, Roche, Sandoz, Janssen-Cilag, VERASTEM: Consultancy; Celgene, Roche, Janssen-Cilag, Gilead: Other: Travel expenses; Celgene: Speakers Bureau. Rumi: Novartis, Abbvie: Consultancy.