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There is increasing recognition that pathogenic germ line variants drive the development of hematopoietic cancers in many individuals. Currently, patients with hereditary hematologic malignancies (HHMs) receive similar standard therapies and hematopoietic stem cell transplant (HSCT) approaches as those with sporadic disease. We hypothesize that patients with myeloid malignancies and deleterious germ line predisposition variants have different posttransplant outcomes than those without such alleles. We studied 472 patients with myeloid neoplasms, of whom 26% had deleterious germ line variants and 34% underwent HSCT. Deleterious germ line variants in CHEK2 and DDX41 were most commonly seen in American and Australian cohorts, respectively. Patients with deleterious germ line DDX41 variants had a higher incidence of severe (stage 3-4) acute graft-versus-host disease (GVHD) (38%) than recipients with deleterious CHEK2 variants (0%), other HHM variants (12%), or patients without such germ line variants (9%) (P = .002). Importantly, the use of posttransplant cyclophosphamide reduced the risk of severe acute GVHD in patients receiving HSCT for deleterious germ line DDX41-associated myeloid neoplasms (0% vs 53%, P = .03). Based on these results, we advocate the use of posttransplant cyclophosphamide when individuals with deleterious germ line DDX41 variants undergo allogeneic HSCT for myeloid malignancies, even when transplantation has been performed using wild-type donors.

Patients receiving chimeric antigen receptor T cells (CAR-T cells) therapy may be particularly susceptible to coronavirus disease 2019 (COVID-19) because of several factors including the immunosuppression associated to the underlying disease and delayed cytopenias. Regrettably, data on outcomes of CAR-T recipients with COVID-19 are extremely scarce. The aim of this study was to investigate the characteristics and outcomes of COVID-19 in patients treated with CAR-T therapy. The European Hematology Association - Scientific Working Group Infection in Hematology endorsed a survey to collect and analyze data from patients developing COVID-19 after CAR-T therapy. Overall, 459 patients treated with CAR-T cells were reported from 18 European centers. The prevalence of COVID-19 cases was 4.8%. Median time from CAR-T therapy and COVID-19 diagnosis was 169 days. Severe infection occurred in 66.7% of patients and 43.3% of the subjects required admission to ICU. The COVID-19 mortality was 33%. In multivariable analysis, the disease status at the time of COVID-19 trended marginally towards adverse outcome (P=0.075). In conclusion, we documented a high fatality rate for CAR-T patients with COVID-19, supporting the need to design successful interventions to mitigate the risk of infection in this vulnerable group of patients.

Key Points CPX-351 treatment is well tolerated and results in morphologic remission in newly diagnosed pediatric secondary myeloid malignancies.Favorable outcomes are achieved despite the presence of high-risk genetic lesions and previous therapies., Visual Abstract, Secondary myelodysplastic syndromes and acute myeloid leukemia (sMDS/AML) are rare in children and adolescents and have a dismal prognosis. The mainstay therapy is hematopoietic cell transplantation (HCT), but there has been no innovation in cytoreductive regimens. CP X-351, a fixed 5:1 molar ratio of liposomal cytarabine to daunorubicin, has shown favorable safety and efficacy in elderly individuals with secondary AML and children with relapsed de novo AML. We report the outcomes of 7 young patients (6 with newly diagnosed sMDS/AML and 1 with primary MDS/AML) uniformly treated with CP X-351. Five patients had previously received chemotherapy for osteosarcoma, Ewing sarcoma, neuroblastoma, or T-cell acute lymphoblastic leukemia; 1 had predisposing genomic instability disorder (Cornelia de Lange syndrome) and 1 had MDS-related AML and multiorgan failure. The median age at diagnosis of myeloid malignancy was 17 years (range, 13-23 years). Patients received 1 to 3 cycles of CP X-351 (cytarabine 100 mg/m2 plus daunorubicin 44 mg/m2) on days 1, 3, and 5, resulting in complete morphologic remission without overt toxicity or treatment-related mortality. This approach allowed for adding an FLT3 inhibitor as individualized therapy in 1 patient. Six patients were alive and leukemia-free at 0.5 to 3.3 years after HCT. One patient died as a result of disease progression before HCT. To summarize, CP X-351 is an effective and well-tolerated regimen for cytoreduction in pediatric sMDS/AML that warrants prospective studies.

Key Points Therapy resistance to both individual and sequential BTK and BCL2 inhibition is clonally complex and most commonly oligoclonal.Single-agent resistance mutations occur in mutually exclusive clones; resistance mutations to sequential monotherapies variably co-occur., The genomic landscape of resistance to targeted agents (TAs) used as monotherapy in chronic lymphocytic leukemia (CLL) is complex and often heterogeneous at the patient level. To gain insight into the clonal architecture of acquired genomic resistance to Bruton tyrosine kinase (BTK) inhibitors and B-cell lymphoma 2 (BCL2) inhibitors in CLL, particularly in patients carrying multiple resistance mutations, we performed targeted single-cell DNA sequencing of 8 patients who developed progressive disease (PD) on TAs (either class). In all cases, analysis of single-cell architecture revealed mutual exclusivity between multiple resistance mutations to the same TA class, variable clonal co-occurrence of multiple mutations affecting different TAs in patients exposed to both classes, and a phenomenon of multiple independent emergences of identical nucleotide changes leading to canonical resistance mutations. We also report the first observation of established BCL2 resistance mutations in a patient with mantle cell lymphoma (MCL) following PD on sequential monotherapy, implicating BCL2 as a venetoclax resistance mechanism in MCL. Taken together, these data reveal the significant clonal complexity of CLL and MCL progression on TAs at the nucleotide level and confirm the presence of multiple, clonally independent, mechanisms of TA resistance within each individual disease context.

Key Points Inhibition of RAB protein function mediates the anti–acute myeloid leukemia activity of statins.Statin sensitivity is associated with enhanced vesicle-mediated traffic., Visual Abstract, Cholesterol homeostasis has been proposed as one mechanism contributing to chemoresistance in AML and hence, inclusion of statins in therapeutic regimens as part of clinical trials in AML has shown encouraging results. Chemical screening of primary human AML specimens by our group led to the identification of lipophilic statins as potent inhibitors of AMLs from a wide range of cytogenetic groups. Genetic screening to identify modulators of the statin response uncovered the role of protein geranylgeranylation and of RAB proteins, coordinating various aspect of vesicular trafficking, in mediating the effects of statins on AML cell viability. We further show that statins can inhibit vesicle-mediated transport in primary human specimens, and that statins sensitive samples show expression signatures reminiscent of enhanced vesicular trafficking. Overall, this study sheds light into the mechanism of action of statins in AML and identifies a novel vulnerability for cytogenetically diverse AML.

Key Points Isolated and comutated DDX41 myeloid neoplasms have different characteristics.DDX41-mutated AML has a relatively favorable outcome comparable to core binding factor AML., Visual Abstract, DDX41 mutations (germline and somatic) are associated with late onset myelodysplastic syndromes/acute myeloid leukemia (MDS/AML). Myeloid neoplasms (MN) with germline predisposition was identified as a distinct category in the 2016 WHO classification revision, including MN with germline DDX41 mutation. We retrospectively analyzed the molecular findings and clinical characteristics of thirty-three DDX41-mutated (mDDX41) patients at our institution. We identified 14 distinct pathogenic DDX41 variants in 32 patients and 8 DDX41 variants of unknown significance (VUS) in 9 patients. Five (16%) patients had a second DDX41 somatic mutation p.R525H and 13 (40%) had at least one additional oncogenic co-mutation in other genes. The median age at the time of diagnosis was 66 years, with male predominance (72%) and the majority of patients had normal cytogenetics (91%). Two-year overall survival (OS) was 86% and 6 (21%) MDS/AML patients with relatively preserved hematopoietic function were observed without further intervention. In comparison to AML patients with prognostically more favorable subtypes [t(8;21), n=27 and inv(16), n=40], mDDX41 patients in our cohort showed similarly favorable OS. Our study highlights that mDDX41-MN patients often have an indolent course and mDDX41-AML has comparable OS to favorable-risk AML.

Key Points TLR4 is overexpressed on MM MSCs, and its activation promotes the crosstalk with MM cells in enhancing protumoral factors.Specifically targeting TLR4 on MM MSCs strengthens conventional MM therapy and weakens MM development in vivo., Visual Abstract, Bone marrow (BM) mesenchymal stromal cells (MSCs) are abnormal in multiple myeloma (MM) and play a critical role by promoting growth, survival, and drug resistance of MM cells. We observed higher Toll-like receptor 4 (TLR4) gene expression in MM MSCs than in MSCs from healthy donors. At the clinical level, we highlighted that TLR4 expression in MM MSCs evolves in parallel with the disease stage. Thus, we reasoned that the TLR4 axis is pivotal in MM by increasing the protumor activity of MSCs. Challenging primary MSCs with TLR4 agonists increased the expression of CD54 and interleukin-6 (IL-6), 2 factors directly implicated in MM MSC-MM cell crosstalk. Then, we evaluated the therapeutic efficacy of a TLR4 antagonist combined or not with conventional treatment in vitro with MSC-MM cell coculture and in vivo with the Vk*MYC mouse model. Selective inhibition of TLR4 specifically reduced the MM MSC ability to support the growth of MM cells in an IL-6-dependent manner and delayed the development of MM in the Vk*MYC mouse model by altering the early disease phase in vivo. For the first time, we demonstrate that specific targeting of the pathological BM microenvironment via TLR4 signaling could be an innovative approach to alter MM pathology development.

Key Points IPF has a typical clinical presentation with involvement of the lower limbs corresponding to vascular territories.The antithrombin level and platelet count at diagnosis seemed to be associated with severe complications in IPF., Visual Abstract, Idiopathic purpura fulminans (IPF) is a rare but severe prothrombotic coagulation disorder that can occur after chickenpox or human herpesvirus 6 (HHV-6) infection. IPF leads to an autoantibody-mediated decrease in the plasma concentration of protein S. We conducted a retrospective multicenter study involving patients with IPF from 13 French pediatric centers and a systematic review of cases in published literature. Eighteen patients were included in our case series, and 34 patients were included as literature review cases. The median age was 4.9 years, and the diagnostic delay after the first signs of viral infection was 7 days. The lower limbs were involved in 49 patients (94%) with typical lesions. In all, 41 patients (78%) had a recent history of varicella-zoster virus infection, and 7 patients (14%) had been infected by HHV-6. Most of the patients received heparin (n = 51; 98%) and fresh frozen plasma transfusions (n = 41; 79%); other treatment options were immunoglobulin infusion, platelet transfusion, corticosteroid therapy, plasmapheresis, and coagulation regulator concentrate infusion. The antithrombin level and platelet count at diagnosis seemed to be associated with severe complications. Given the rarity of this disease, the creation of a prospective international registry is required to consolidate these findings.

Management of secondary central nervous system (SCNS) involvement in relapsed or refractory aggressive B-cell lymphomas remains an area of unmet medical need. We report a single-center retrospective analysis of 7 adult patients with SCNS lymphoma (SCNSL) who underwent chimeric antigen receptor (CAR) T-cell therapy for their refractory disease, and we describe the safety of whole brain radiation therapy (WBRT) as a bridging therapy. Six patients (85.7%) achieved a complete response at day 28, and 1 patient had progressive disease. The median progression-free survival was 83 days (range, 28-219 days), and median overall survival was 129 days (range, 32-219 days). Three patients died as a result of disease progression. Of the 5 patients who received WBRT as bridging therapy, 3 had no immune effector cell–associated neurotoxicity syndrome (ICANS), but 2 patients had grade 1 or grade 3 ICANS. No grade 4 ICANS was reported in this subset of patients. We conclude that SCNSL should not preclude patients from receiving CAR T-cell therapy as a treatment option because of concerns regarding ICANS, and bridging with WBRT is not associated with increased ICANS., Key Points SCNSL should not preclude patients from receiving CAR T-cell therapy because of concerns regarding ICANS.WBRT is not associated with increased ICANS when used as a bridge to CAR T-cell therapy with a short median interval in SCNSL.

Key Points First report of an FLT3-targeted therapy added to nonintensive chemotherapy that has improved survival in older FLT3-ITD patients with AML.Quizartinib is well tolerated, improves response and survival in older FLT3-ITD AML patients and merits consideration in future therapies. Now amended as text above., Visual Abstract, Survival for older patients with acute myeloid leukemia (AML) unsuitable for intensive chemotherapy is unsatisfactory. Standard nonintensive therapies have low response rates and only extend life by a few months. Quizartinib is an oral Fms-like tyrosine kinase 3 (FLT3) inhibitor with reported activity in wild-type patients. As part of the AML LI trial, we undertook a randomized evaluation of low-dose ara-C (LDAC) with or without quizartinib in patients not fit for intensive chemotherapy. Overall, survival was not improved (202 patients), but in the 27 FLT3-ITD patients, the addition of quizartinib to LDAC improved response (P = .05) with complete remission/complete remission with incomplete haematological recovery for quizartinib + LDAC in 5/13 (38%) vs 0/14 (0%) in patients receiving LDAC alone. Overall survival (OS) in these FLT3-ITD+ patients was also significantly improved at 2 years for quizartinib + LDAC (hazard ratio 0.36; 95% confidence intervals: 0.16, 0.85, P = .04). Median OS was 13.7 months compared with 4.2 months with LDAC alone. This is the first report of an FLT3-targeted therapy added to standard nonintensive chemotherapy that has improved survival in this population. Quizartinib merits consideration for future triplet-based treatment approaches. This trial was registered at www.clinicaltrials.gov as ISRCTN #ISRCTN40571019 and EUDRACT @2011-000749-19.

Key Points Effector polyfunctional index score of CD4 cells was more associated with responses to combined azacitidine/nivolumab than CD8 cells.Single-cell biomarker assays can be used in predicting responses to immune-based therapies., Acute myeloid leukemia (AML) remains a difficult disease to treat disease. In a phase 2 clinical trial in patients with relapsed/refractory AML, combining the hypomethylating agent, azacitidine, with the PD-1 checkpoint inhibitor, nivolumab, demonstrated encouraging response rates (33%), median event-free, and overall survival, compared with a historical cohort of contemporary patients treated with azacitidine-based therapies, with an acceptable safety profile. Biomarkers of response are yet to be determined. In this study, we leveraged a multiplexed immune assay to assess the functional states of CD4+ and CD8+ cells at a single-cell level in pretherapy bone marrows in 16 patients with relapsed/refractory AML treated with azacitidine/nivolumab. Effector CD4+ but not CD8+ cells had distinct polyfunctional groups and were associated with responses and better outcomes. Further evaluation of the polyfunctional strength index composition across cell types revealed that interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) were the major drivers of enhanced polyfunctionality index of pretherapy CD4+ subset, whereas Granzyme B, IFN-γ, MIP-1b, and TNF-α drove the nonsignificantly enhanced pretreatment Polyfunctional Strength Index of CD8+ subset in the responders. Single-cell polyfunctional assays were predictive of response in AML and may have a potential role as a biomarker in the wider sphere of immunotherapy.

Key Points A novel class of ZNF384 aberrations affects the last exon of ZNF384 and results in disruption of the C-terminal portion of ZNF384 protein.Leukemias with the novel class of ZNF384 aberrations phenocopy leukemias with the canonical ZNF384 fusions., Fusion of the ZNF384 gene as the 3' partner to several different 5' partner genes occurs recurrently in B-cell precursor acute lymphoblastic and mixed phenotype B/myeloid leukemia. These canonical fusions (ZNF384r) contain the complete ZNF384 coding sequence and are associated with a specific gene expression signature. Cases with this signature, but without canonical ZNF384 fusions (ZNF384r-like cases), have been described previously. Although some have been shown to harbor ZNF362 fusions, the primary aberrations remain unknown in a major proportion. We studied 3 patients with the ZNF384r signature and unknown primary genetic background and identified a previously unknown class of genetic aberration affecting the last exon of ZNF384 and resulting in disruption of the C-terminal portion of the ZNF384 protein. Importantly, in 2 cases, the ZNF384 aberration, indel, was missed during the bioinformatic analysis but revealed by the manual, targeted reanalysis. Two cases with the novel aberrations had a mixed (B/myeloid) immunophenotype commonly associated with canonical ZNF384 fusions. In conclusion, we present leukemia cases with a novel class of ZNF384 aberrations that phenocopy leukemia with ZNF384r. Therefore, we show that part of the so-called ZNF384r-like cases represent the same genetic subtype as leukemia with canonical ZNF384 fusions.

Key Points Diagnosis of TCL often relies on PCR-based TCR clonality testing, which displays low specificity and requires high-quality DNA.Targeted NGS and T-cell clonality assessment are complementary techniques that should be applied in hard front-line diagnosis., Immunomorphological diagnosis of T-cell lymphoma (TCL) may be challenging, especially on needle biopsies. Multiplex polymerase chain reaction (PCR) assays to assess T-cell receptor (TCR) gene rearrangements are now widely used to detect T-cell clones and provide diagnostic support. However, PCR assays detect only 80% of TCL, and clonal lymphocyte populations may also appear in nonneoplastic conditions. More recently, targeted next-generation sequencing (t-NGS) technologies have been deployed to improve lymphoma classification. To the best of our knowledge, the comparison of these techniques’ performance in TCL diagnosis has not been reported yet. In this study, 82 TCL samples and 25 nonneoplastic T-cell infiltrates were divided into 2 cohorts (test and validation) and analyzed with both multiplex PCR and t-NGS to investigate TCR gene rearrangements and somatic mutations, respectively. The detection of mutations appeared to be more specific (100.0%) than T-cell clonality assessment (41.7%-45.5%), whereas no differences were observed in terms of sensitivity (95.1%-97.4%). Furthermore, t-NGS provided a reliable basis for TCL diagnosis in samples with partially degraded DNA that was impossible to assess with PCR. Finally, although multiplex PCR assays appeared to be less specific than t-NGS, both techniques remain complementary, as PCR recovered some t-NGS negative cases.

Key Points Candidate discovery of translational feasibility for noninvasive measurement of miRNA from plasma vesicles as a biomarker for AML patients.Preclinical validation of miR-1246 (candidate among 15 miRNA) as a potential minimally invasive AML biomarker for early monitoring of MRD., Recurrent disease remains the principal cause for treatment failure in acute myeloid leukemia (AML) across age groups. Reliable biomarkers of AML relapse risk and disease burden have been problematic, as symptoms appear late and current monitoring relies on invasive and cost-ineffective serial bone marrow (BM) surveillance. In this report, we discover a set of unique microRNA (miRNA) that circulates in AML-derived vesicles in the peripheral blood ahead of the general dissemination of leukemic blasts and symptomatic BM failure. Next-generation sequencing of extracellular vesicle-contained small RNA in 12 AML patients and 12 controls allowed us to identify a panel of differentially incorporated miRNA. Proof-of-concept studies using a murine model and patient-derived xenografts demonstrate the feasibility of developing miR-1246, as a potential minimally invasive AML biomarker.

The COVID-19 pandemic has highlighted racial health disparities within the United States. Although social determinants of health are the most likely drivers of this disparity, it is possible that genetic traits enriched in the black population like sickle cell trait (SCT) could worsen the morbidity and mortality of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Patients admitted for SARS-CoV-2 infection who identified as black or African American were included in the study (n = 166). Blood remnants were tested for SCT, and clinical data were abstracted from the chart. There was no difference in mortality between those with SCT and those without. There was no difference in respiratory complications between groups, but those without SCT had a much higher burden of chronic lung disease (P = .004). Those with SCT had higher creatinine on admission (P = .004), but no difference in in-hospital renal complications (P = .532). Notably, 12% of the cohort had SCT, which is higher than the expected 7.31% (P = .025). Our study did not show any evidence of increased end organ damage, morbidity, or mortality from SARS-CoV-2 infection among patients with SCT but did show differences in admission creatinine and preexisting lung disease., Key Points • There is no impact of SCT on respiratory, renal, or circulatory complications or mortality in patients with SARS-CoV-2 infection. • The prevalence of SCT in the hospitalized cohort was significantly higher than the prevalence in the community (12% vs 7.31%).

The molecular causes of myeloproliferative neoplasms (MPNs) have not yet been fully elucidated. Approximately 7% to 8% of the patients carry predisposing genetic germline variants that lead to driver mutations, which enhance JAK-STAT signaling. To identify additional predisposing genetic germline variants, we performed whole-exome sequencing in 5 families, each with parent-child or sibling pairs affected by MPNs and carrying the somatic JAK2 V617F mutation. In 4 families, we detected rare germline variants in known tumor predisposition genes of the DNA repair pathway, including the highly penetrant BRCA1 and BRCA2 genes. The identification of an underlying hereditary tumor predisposition is of major relevance for the individual patients as well as for their families in the context of therapeutic options and preventive care. Two patients with essential thrombocythemia or polycythemia vera experienced progression to acute myeloid leukemia, which may suggest a high risk of leukemic transformation in these familial MPNs. Our study demonstrates the relevance of genetic germline diagnostics in elucidating the causes of MPNs and suggests novel therapeutic options (eg, PARP inhibitors) in MPNs. Furthermore, we uncover a broader tumor spectrum upon the detection of a germline mutation in genes of the DNA repair pathway.

T cell–engaging immunotherapies exert unprecedented single-agent activity in multiple myeloma (MM), thereby putting a yet unexplored selective pressure on the clonal architecture. In this study, we report on homozygous BCMA (TNFRSF17) gene deletion after BCMA-targeting T cell–redirecting bispecific antibody therapy in a heavily pretreated MM patient. Loss of BCMA protein expression persisted over subsequent relapses, with no response to treatment with anti-BCMA antibody drug conjugate. In light of the multiple alternative targets that are emerging in addition to BCMA, we extended our analyses to delineate a more complete picture of genetic alterations that may have an impact on immunotherapy targets in MM. We performed whole-genome sequencing and RNA sequencing in 100 MM patients (50 were newly diagnosed; 50 were relapsed/refractory) and identified a significant proportion of patients with aberrations in genes encoding immunotherapy targets; GPRC5D ranked first with 15% heterozygous deletions, followed by CD38 (10%), SDC1 (5%), and TNFRSF17 (4%). Notably, these heterozygous deletions did not lower the expression levels of respective genes, but they may represent a first hit that drives the acquisition of homozygous deletions and subsequent antigen-loss relapse upon targeted immunotherapy. In summary, we show preexisting vulnerability in genes encoding immunotargets before and homozygous deletions after T cell–engaging immunotherapy.

In patients with Gárdos channelopathy (p.R352H), an increased concentration of intracellular Ca2+ was previously reported. This is a surprising finding because the Gárdos channel (KCa3.1) is a K+ channel. Here, we confirm the increased intracellular Ca2+ for patients with the KCa3.1 mutation p.S314P. Furthermore, we provide the concept of KCa3.1 activity resulting in a flickering of red blood cell (RBC) membranepotential, which activates the CaV2.1 channel allowing Ca2+ to enter the RBC. Activity of the nonselective cation channel Piezo1 modulates the aforementioned interplay in away that a closed Piezo1 is in favor of the KCa3.1-CaV2.1 interaction. In contrast, Piezo1 openings compromise the membrane potential flickering, thus limiting the activity of CaV2.1. With the compound NS309, we mimic a gain-of-function mutation of KCa3.1. Assessing the RBC Ca2+ response by Fluo-4–based flow cytometry and by measuring the membrane potential using the Macey-Bennekou-Egée method, we provide data that support the concept of the KCa3.1/CaV2.1/Piezo1 interplay as a partial explanation for an increased number of high Ca2+ RBCs. With the pharmacological inhibition of KCa3.1 (TRAM34 and Senicapoc), CaV2.1 (ω-agatoxin TK), and Piezo1 (GsMTx-4), we could project the NS309 behavior of healthy RBCs to the RBCs of Gárdos channelopathy patients.

Monitoring of measurable residual disease (MRD) is essential to the management of acute lymphoblastic leukemia (ALL) and is typically performed through repeated bone marrow (BM) assessments. Using a next-generation sequencing (NGS) MRD platform, we performed a prospective observational study evaluating the correlation between peripheral blood (PB) and BM MRD in adults with ALL receiving cellular therapies (hematopoietic cell transplantation [HCT] and chimeric antigen receptor T-cell [CAR-T] therapies). Among the study cohort (N = 69 patients; 126 paired PB/BM samples), we found strong correlation between PB and BM MRD (r = 0.87; P < .001), with a sensitivity and specificity of MRD detection in the PB of 87% and 90%, respectively, relative to MRD in the BM. MRD became detectable in the PB in 100% of patients who subsequently relapsed following HCT, with median time from MRD+ to clinical relapse of 90 days, and in 85% of patients who relapsed following CAR T, with median time from MRD+ to clinical relapse of 60 days. In adult patients with ALL undergoing cellular therapies, we demonstrate strong concordance between NGS-based MRD detected in the PB and BM. Monitoring of ALL MRD in the PB appears to be an adequate alternative to frequent invasive BM evaluations in this clinical setting.

Chimeric antigen receptor (CAR) T-cells have emerged as an efficacious modality in patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM). Clonal hematopoiesis of indeterminate potential (CHIP), a state in which mutations in hematopoietic cells give rise to a clonal population of cells, is more common in patients exposed to cytotoxic therapies, has been shown to influence inflammatory immune programs, and is associated with an adverse prognosis in patients with NHL and MM receiving autologous transplantation. We therefore hypothesized that CHIP could influence clinical outcomes in patients receiving CAR T-cell therapy. In a cohort of 154 patients with NHL or MM receiving CAR T-cells, we found that CHIP was present in 48% of patients and associated with increased rates of complete response and cytokine release syndrome severity, but only in patients younger than age 60 years. Despite these differences, CHIP was not associated with a difference in progression-free or overall survival, regardless of age. Our data suggest that CHIP can influence CAR T-cell biology and clinical outcomes, but, in contrast to autologous transplantation, CHIP was not associated with worse survival and should not be a reason to exclude individuals from receiving this potentially life-prolonging treatment.

TEMPI syndrome (telangiectasias, elevated erythropoietin level and erythrocytosis, monoclonal gammopathy, perinephric fluid collections, and intrapulmonary shunting) is a newly defined multisystemic disease with its pathophysiology largely unknown. Here, we report the whole-genome sequencing (WGS) analysis on the tumor-normal paired cells from a patient with TEMPI syndrome. WGS revealed somatic nonsynonymous single-nucleotide variants, including SLC7A8, NRP2, and AQP7. Complex structural variants of chromosome 2 were found, particularly within regions where some putative oncogenes reside. Of potential clinical relevance, duplication of 22q11.23 was identified, and the expression of the located gene macrophage migration inhibitory factor (MIF) was significantly upregulated in 3 patients with TEMPI syndrome. Importantly, the level of serum MIF in one patient with TEMPI syndrome was significantly decreased in accordance with the downtrend of plasma cells, M-protein, hemoglobin, and erythropoietin and the improvement of telangiectasias, perinephric fluid collections, and intrapulmonary shunting after treatment with plasma cell–directed therapy. In conclusion, our study provides insights into the genomic landscape and suggests a role of MIF in the pathophysiology of TEMPI syndrome.

Sickle cell anemia (SCA) results from an abnormal sickle hemoglobin (HbS). HbS polymerizes upon deoxygenation, resulting in red blood cell (RBC) sickling and membrane damage that cause vaso-occlusions and hemolysis. Sickle RBCs contain less adenosine triphosphate and more 2,3-diphosphoglycerate than normal RBCs, which allosterically reduces hemoglobin (Hb) oxygen (O2) affinity (ie, increases the partial pressure of oxygen at which hemoglobin is 50% saturated with oxygen [P50]), potentiating HbS polymerization. Herein, we tested the effect of investigational agent FT-4202, an RBC pyruvate kinase (PKR) activator, on RBC sickling and membrane damage by administering it to Berkeley SCA mice. Two-week oral FT-4202 administration was well tolerated, decreasing HbS P50 to levels similar to HbA and demonstrating beneficial biological effects. In FT-4202–treated animals, there was reduced sickling in vivo, demonstrated by fewer irreversibly sickled cells, and improved RBC deformability, assessed at varying shear stress. Controlled deoxygenation followed by reoxygenation of RBCs obtained from the blood of FT-4202–treated mice showed a shift in the point of sickling to a lower partial pressure of oxygen (pO2). This led to a nearly 30% increase in RBC survival and a 1.7g/dL increase in Hb level in the FT-4202–treated SCA mice. Overall, our results in SCA mice suggest that FT-4202 might be a potentially useful oral antisickling agent that warrants investigation in patients with SCA.

The efficacy and safety of caplacizumab in individuals with acquired thrombotic thrombocytopenic purpura (aTTP) have been established in the phase 2 TITAN and phase 3 HERCULES trials. Integrated analysis of data from both trials was conducted to increase statistical power for assessing treatment differences in efficacy and safety outcomes. Caplacizumab was associated with a significant reduction in the number of deaths (0 vs 4; P < .05) and a significantly lower incidence of refractory TTP (0 vs 8; P < .05) vs placebo during the treatment period. Consistent with the individual trials, treatment with caplacizumab resulted in a faster time to platelet count response (hazard ratio, 1.65; P < .001), a 72.6% reduction in the proportion of patients with the composite end point of TTP-related death, TTP exacerbation, or occurrence of at least 1 treatment-emergent major thromboembolic event during the treatment period (13.0% vs 47.3%; P < .001), and a 33.3% reduction in the median number of therapeutic plasma exchange days (5.0 vs 7.5 days) vs placebo. No new safety signals were identified; mild mucocutaneous bleeding was the main safety finding. This integrated analysis provided new evidence that caplacizumab prevents mortality and refractory disease in acquired TTP and strengthened individual trial findings, with a confirmed favorable safety and tolerability profile. These trials were registered at www.clinicaltrials.gov as #NCT01151423 and #NCT02553317.

Key Points Children with Down syndrome develop early signs of clonal evolution that resemble traditional clonal hematopoiesis. Children with trisomy 21 who exhibit clonal hematopoiesis display cytokine and gene expression profiles indicative of disrupted immunity.

Key Points The RBD of SARS-CoV-2 shares sequence similarity with an ancient lectin family known to bind blood group antigens. SARS-CoV-2 RBD binds the blood group A expressed on respiratory epithelial cells, directly linking blood group A and SARS-CoV-2.

The phase 2 GRIFFIN study of daratumumab plus lenalidomide/bortezomib/dexamethasone (D-RVd) for transplant-eligible, newly diagnosed multiple myeloma included a safety run-in phase followed by a randomized phase. The ongoing randomized phase has met its prespecified primary end point of an improved stringent complete response (sCR) rate after consolidation for D-RVd (reported elsewhere). Final analysis of the safety run-in cohort is reported herein and provides longer follow-up (median, 40.8 months) encompassing daratumumab plus lenalidomide (D-R) maintenance therapy. Patients in the safety run-in cohort (N = 16) received 4 induction cycles (D-RVd), high-dose melphalan supported by autologous stem cell transplant, 2 consolidation cycles (D-RVd), and 24 months of maintenance (D-R). By the end of consolidation, all patients had responded, with a best response of sCR in 9 (56.3%) patients; 8 (50.0%) patients were minimal residual disease (MRD) negative (10‒5 threshold). After maintenance, 15 (93.8%) patients had achieved a best response of sCR, and 13 (81.3%) patients were MRD (10‒5) negative. Estimated 36-month progression-free and overall survival rates were 78.1% and 93.8%, respectively. One death from progressive disease occurred in the patient who did not achieve sCR. Observed safety profiles were consistent with daratumumab and RVd. With >3 years of median follow-up, D-RVd achieved durable responses that deepened with D-R maintenance. This study was registered at www.clinicaltrials.gov as #NCT02874742.

Key Points High rates of bloodstream infection (BSI) were seen after fecal microbiota transplantation (FMT) in patients with graft-versus-host disease.Metagenomic analysis pointed to recipients’ indigenous microbiota as the BSI source, ruling out direct involvement of FMT donations., Visual Abstract, We observed high rates of bloodstream infections (BSIs) following fecal microbiota transplantation (FMT) for graft-versus-host-disease (33 events in 22 patients). To trace the BSIs' origin, we applied a metagenomic bioinformatic pipeline screening donor and recipient stool samples for bacteremia-causing strains in 13 cases. Offending strains were not detected in FMT donations. Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii could be detected in stool samples before emerging in the blood. In this largest report of BSIs post-FMT, we present an approach that may be applicable for evaluating BSI origin following microbiota-based interventions. Our findings support FMT safety in immunocompromised patients but do not rule out FMT as an inducer of bacterial translocation.

Vancomycin exposure in the pre-engraftment period was associated with an increased risk for CMV reactivation after allogeneic HCT. Some gram-positive bacteria may protect against CMV reactivation.

Key Points Sputum interleukin-6 (IL-6) level is high during acute chest syndrome (ACS) in pediatric sickle cell disease, supporting anti–IL-6 trials. Sputum IL-8, CCL2, and CCL3 levels are also high during ACS, possibly contributing to recruitment of inflammatory cells in the lungs.

Key Points The CD34+ compartment of human cord blood contains a range of HSPC immunophenotypes, among which the Lin−CD34+CD38+CD127+ CLP is rare. There is no correlation between the frequencies of CD34+ cells and immunophenotypic HSC in umbilical cord blood products.

Key Points IDH1/2-inhibitor–based combinations conferred significant clinical responses in patients with IDH1/2-mutated post–MPN AML. Complete remission was achieved in 3/7 patients (1 attaining MRD–) with new IDH1/2-mutated post–MPN AML treated with IDH1/2-i combinations.

Key Points Shingrix is poorly immunogenic following allogeneic hematopoietic cell transplantation independent of age, CD4, and B-cell recovery. In hematopoietic cell transplantation recipients with antibody response to the vaccine, varicella zoster virus reactivation risk is not null.

Key Points Single-cell whole-genome amplification can be used to interrogate the genomic architecture of Waldenström’s macroglobulinemia. The mutational signature of CXCR4MUT cells may be associated with alterations in DNA repairing genes and tumor suppressors.

Sickle cell disease (SCD) is an autosomal-recessive blood disorder affecting over 100 000 individuals in the United States.1 Mutant sickle hemoglobin polymerizes within red blood cells (RBCs) under deoxygenated conditions resulting in cell rigidity, hemolysis, and vaso-occlusion.2 These events catalyze an inflammatory response, which can lead to acute painful vaso-occlusive episodes.2,3 Acute pain is the predominant cause for seeking medical treatment, resulting in estimated medical care costs of over $1.1 billion dollars annually for those with SCD.4,5 The role of impaired hemorheology in SCD and its contribution toward vaso-occlusion is well documented.6,7 Poor blood rheology including elevated whole-blood viscosity, plasma viscosity, RBC membrane rigidity, and cytosolic viscoelasticity impedes microvascular blood flow by increasing intravascular resistance and decreasing RBC velocity.8,9 Abnormal cellular adhesion markers presented on sickle RBCs due to membrane damage and on prematurely released reticulocytes further contribute to impaired flow and the precipitation of vaso-occlusion.3,10,11 Recently, blood additives known as drag-reducing polymers (DRPs) have been shown to alter blood rheology beneficially and to improve the hemodynamics and outcomes of animals following hemorrhagic shock,12 liver ischemia/reperfusion injury,13 and traumatic brain injury significantly,14 while simultaneously providing increased capillary recruitment, perfusion, and oxygenation.15 However, the effects of DRP are unknown in the context of SCD, where a rheology-based therapy to improve microcirculatory blood flow has the potential to greatly reduce the incidence of vaso-occlusion. In this study, we have used quantitative liver intravital microscopy (qLIM) to show that the administration of nanomolar concentrations of DRP reduces vaso-occlusion within liver sinusoids of transgenic SCD mice following inflammatory stimulus via lipopolysaccharide (LPS).

Key Points HLA-specific alloantibodies can be maintained despite profound CD19+ cell aplasia, likely due to production by CD19− plasma cells.

Key Points VTE developed in 11% of lymphoma patients after CAR T-cell therapy and was managed safely with anticoagulation. Coagulation abnormalities after CAR T-cell therapy occur but do not commonly lead to bleeding events.

Antibody-mediated neutralization of pathogens is a key function of adaptive immunity. Immunoglobulin G (IgG) molecules bind to invading pathogens with high affinity and specificity. Platelets are known to contain IgG in their α-granules1; however, the biological significance of this antibody reservoir is unclear. In addition to their primary role in hemostasis, platelets are active and autonomous participants in host immune responses to bacterial and viral infections.2 Platelets express various receptors, such as Toll-like receptors 2 and 7, for direct responses to viruses, including cytomegalovirus (CMV) and influenza A virus (IAV).3-7 Because of their high sensitivity, rapid responsiveness, and sheer number, platelets function as sentinels and as the first line of defense against invading pathogens. Upon virus recognition, platelets contribute to pathogen clearance by engulfing virus particles and modulating leukocyte effector function.5,8,9 Although platelet-derived antimicrobial peptides restrict bacterial infection,10 the impact of platelet-derived IgG is unknown. Here, we investigated platelet effects on virus neutralization via IgG release and found an unexplored mechanism to potentiate humoral immunity, which might be used for platelet-based drug-delivery therapy.

Key Points Age-adapted high-dose chemotherapy and autologous stem cell transplantation is safe and highly effective in elderly patients with PCNSL.

Key Points Posttransplantation, glasdegib maintenance therapy in patients at high risk for relapse did not meaningfully reduce relapse incidence. Use of glasdegib in the posttransplantation setting was complicated by adverse events requiring drug holds and occasional discontinuation.

Key Points Treatment-naive and relapsed/refractory MDS patients receiving venetoclax and HMAs have an ORR of 59% with 63% of responders proceeding to transplant. Allogeneic stem cell transplantation after treatment with venetoclax in combination with HMA is associated with prolonged survival.

Key Points 3D organoid T-cell differentiation from a few hundred peripheral blood CD34+ cells was successfully achieved. 3D organoid T-cell differentiation could help physicians distinguish intrinsic from extrinsic defects underlying a clinical SCID phenotype.

Key Points High-density lipoprotein and apolipoprotein A-I enhance activated protein C cytoprotective activity. High-density lipoprotein and apolipoprotein A-I significantly increase the rate at which activated protein C degrades cytotoxic extracellular histones.

Key Points Ability to accurately attribute adverse events post–gene therapy is required to describe the benefit-risk of these novel treatments. A SCD patient developed myelodysplastic syndrome post-LentiGlobin treatment; we show how insertional oncogenesis was excluded as the cause.

Background: A number of studies have reported elevated incidence of 25-OH-vitamin D deficiency among patients with multiple myeloma (MM). Several studies have found association between vitamin D levels and factors associated with survival, including ISS stage at diagnosis. However, the impact of vitamin D deficiency on MM prognosis is not entirely clear. Also, in general, both the incidence and the impact of vitamin D deficiency differ substantially by race. Here, we investigate the impact of vitamin D deficiency on prognosis in a large and racially heterogenous patient population with MM in the Veterans Affairs (VA) system. Methods: We used the VA's nationwide Corporate Data Warehouse to identify patients diagnosed with symptomatic MM from 1999 to 2017. Various demographic and laboratory data was collected including age, race, 25-OH-vitamin D levels, and ISS stage at diagnosis as well as survival outcome data. Details of therapies received was also available which indicted similar access to all newer agents approved for myeloma for both African American (AA) and Caucasian patients. Results: We identified 15,717 patients diagnosed with MM (3353 AA and 9070 Caucasian), of whom 6675 had vitamin D measurements within 2 months of diagnosis (1959 AA and 4398 Caucasian). Median serum vitamin D levels were significantly lower among AA patients (21.8 ng/mL) than Caucasians (28.6 ng/mL; p We evaluated the ability of serum vitamin D level to predict overall survival (OS) in patients with MM using a cut-off of 20ng/mL. Patients with vitamin D deficiency ( The analyses were repeated for AA and Caucasian patients separately. Among AA patients, serum vitamin D was not a significant predictor of OS in univariate (P=0.5096) or multivariate analysis (P=0.6923), while it was still a strong predictor among Caucasian patients in both univariate (HR 1.38; P=0.0006) and multivariate analysis (HR 1.45; P=0.0048). Median OS is 3.54 years (95% CI 2.99-5.52; n=255) for AA patients with vitamin D deficiency and 3.95 years (3.25-5.35; n=296) with normal levels. Among Caucasians, median OS is 2.71 years (2.18-3.47; n=273) for deficient and 3.87 years (3.59-4.42; n=885) for normal. Kaplan-Meier plots (Fig. 1B and 1C) illustrate the observed OS curves for the two subgroups. Since levels of vitamin D were lower in AA patients, a lower cut-off of 10 ng/mL was also tested. Even using this lower cutoff, vitamin D deficiency was not a statistically significant predictor of OS in univariate (HR 1.33; P=0.0781) or multivariate analysis (HR 1.09; P=0.7039), though the number of AA patients with vitamin D Conclusions: Vitamin D deficiency is a significant predictor of survival among patients diagnosed with MM, even after accounting for race, age, and ISS stage. However, this relationship is only observed in Caucasian patients and not observed among AA patients. Studies are ongoing to evaluate impact of Vitamin D deficiency of disease presentation including bone disease as well as genetic characteristics. This investigation highlights the need to assess the underlying biological mechanism responsible for the observed impact of vitamin D deficiency across race in MM. Download : Download high-res image (145KB) Download : Download full-size image Disclosures Yellapragada: Novartis: Employment; Celgene: Research Funding; Takeda: Research Funding. Munshi: OncoPep: Other: Board of director.

Key Points The K666N mutation of SF3B1 has distinct clinicopathologic features in MDS. The K666N mutation of SF3B1 has a distinct RNA splicing profile.

Chromosomal rearrangements of the lysine methyltransferase 2A (KMT2A or MLL) gene are observed in ;10% of all acute leukemias, with particularly high frequency (;80%) in infant acute lymphoblastic leukemia (ALL),1 where, despite aggressive chemotherapy, patients still experience poor outcome and long-term side effects.2 Mixed lineage leukemia (MLL) rearrangements (MLL-r)also indicate particularly poor outcomes for patients with acute myeloid leukemia (AML).3 Mechanistically, MLL-r frequently generates fusion proteins involving partners that function in the super elongation complex,4 the result of which is aberrant recruitment to MLL target genes of the positive transcription elongation factor b (PTEFb), composed of cyclin-dependent kinase 9 (CDK9)as the catalytic subunit.5 CDK9 positively regulates transcription elongation through phosphorylation of serine 2 of RNA polymerase II (RNAPII).6 Given the central role of CDK9 in the leukemic MLL-r gene-expression program,7 and the well-described ability of CDK9 inhibitors to reduce levelsof the short-lived prosurvival protein MCL1,8 a number of CDK9 inhibitors have been selected forclinical trials focusing on acute leukemias, including those with MLL-r.8,9 In MLL-r leukemia, the bromodomain and extraterminal (BET) family member bromodomain-containing 4 (BRD4)10 acts to recruit PTEFb to super enhancers and together with CDK9 drives increased expression of many oncogenes including MYC.11,12 The roles of CDK9 and BRD4 in MLL-r leukemias present a strong case for testing inhibitors of these proteins in combination as a potential treatment of MLL-r acute leukemias. Refereed/Peer-reviewed

Introduction: the high cure rates achieved in early-stage (ES) Hodgkin lymphoma (HL) are one of the great successes of hemato-oncology, but late treatment-related toxicity undermines long-term survival. Improving overall survival and quality of life further will require maintaining disease control while potentially de-escalating chemotherapy and/or omitting radiotherapy to reduce late toxicity. Accurate stratification of patients is required to facilitate individualized treatment approaches. Response assessment using 18F-fluorodeoxyglucose positron emission tomography (PET) is a powerful predictor of outcome in HL,1,2 and has been used in multiple studies, including the United Kingdom National Cancer Research Institute Randomised Phase III Trial to Determine the Role of FDG–PET Imaging in Clinical Stages IA/IIA Hodgkin’s Disease (UK NCRI RAPID) trial, to investigate whether patients achieving complete metabolic remission (CMR) can be treated with chemotherapy alone.3-5 These PET-adapted trials have demonstrated that omitting radiotherapy results in higher relapse rates, but without compromising overall survival.3-5 For the 75% of patients who achieved CMR in RAPID, neither baseline clinical risk stratification (favorable/unfavorable) nor PET (Deauville score 1/2) predicted disease relapse; additional biomarkers are needed.1 Tumor bulk has long been recognized as prognostic in HL,1,6 but there remains uncertainty about the significance and definition of bulk in the era of PET-adapted treatment.7 We performed a subsidiary analysis of RAPID to assess the prognostic value of baseline maximum tumor dimension (MTD) in patients achieving CMR. Methods: ee have previously reported the RAPID trial design, primary results, and outcomes according to pretreatment risk stratification and PET score.1,3 Patients were aged 16 to 75 years with untreated ES-HL and without B-symptoms or mediastinal bulk (mass > 1/3 internal mediastinal diameter at T5/6).6 Metabolic response after 3 cycles of ABVD chemotherapy (doxorubicin, bleomycin, vinblastine, and dacarbazine) was centrally assessed using PET (N = 562). Patients with CMR (ie, Deauville score 1-2) were randomly assigned to receive involved field radiotherapy (IFRT; n = 208) or no further therapy (NFT; n = 211). PET-positive patients (score, 3-5; n = 143) received a fourth cycle of ABVD and IFRT. Baseline disease assessment was performed by computed tomography, and bidimensional target lesion measurements were reported by local radiologists in millimeters. The association of baseline MTD with HL-related event-free survival (EFS: progression or HL-related death) and progression-free survival (PFS) (progression or any-cause death) was assessed using Kaplan-Meier and Cox regression analyses. Non-HL deaths were either related to primary treatment toxicity or occurred in HL remission.1 United Kingdom ethical approval for the RAPID trial was via the UK Multicentre Research ethics committee. Results and discussion: baseline patient characteristics have been previously described.1 Median age was 34 years (range, 16-75 years); 184 (37.4%) of 492 patients had unfavorable risk by European Organisation for Research and Treatment of Cancer criteria, and 155 (32.3%) of 480 by German Hodgkin Study Groupcriteria. Median MTD for patients achieving CMR was 3.0 cm (interquartile range, 2.0-4.0 cm) and 3.0 cm (interquartile range, 1.8-4.5 cm) in the NFT and IFRT groups, respectively, whereas PET-positive patients had a median MTD of 3.9 cm (interquartile range, 2.8-5.1 cm). After a median follow-up of 61.6 m, 44 HL progression events occurred: 21 NFT, 9 IFRT and 14 PET-positive. No patient received salvage treatment without documented progression. Only 5 HL-related deaths occurred (1 IFRT, 4 PET-positive), and 12 non-HL deaths (4 NFT, 6 IFRT, 2 PET-positive).1 For patients with CMR (N = 419), there was a strong association between MTD and EFS (hazard ratio [HR], 1.19; 95% confidence interval [CI], 1.02-1.39; P = .02), adjusting for treatment group, with an approximate 19% increase in HL risk per centimeter increase in MTD. The association was similar in both treatment groups (NFT HR, 1.20 [95% CI, 0.99-1.44; P = .06]; IFRT HR, 1.19 [95% CI, 0.92-1.55; P = .19]). The observed effect sizes did not markedly change after adjusting for baseline clinical risk factors, and similar results were observed for PFS (supplemental Table 1). In contrast, for PET-positive patients, there was no association between MTD and EFS (HR, 0.88; 95% CI, 0.70-1.11; P = .29) or PFS (HR, 0.87; 95% CI, 0.70-1.08; P = .21). In an exploratory analysis within the NFT group, MTD was dichotomized using increasing 1-cm intervals to investigate the relationship between MTD thresholds and EFS. The largest effect size was observed with an MTD threshold of ≥5 cm (Table 1). Similar results were observed for PFS; this threshold also performed best in time-dependent receiver operating characteristic curve analyses. It was not possible to assess MTD thresholds in the IFRT group with only 9 events. Among all randomized patients, 79 (18.9%) had MTD of ≥5 cm, the majority with mediastinal (n = 43), supraclavicular (n = 17), or cervical (n = 16) locations. Five-year EFS for patients with MTD of ≥5 cm randomly assigned to NFT and IFRT was 79.3% (n = 39; 95% CI, 66.6%-92.0%) and 94.9% (n = 40; 95% CI, 88.0%-100%), respectively (P = .03; Figure 1).

Key Points Patients with FL anti-HBc+ present with worse 10-year PFS and OS.Patients with anti-HBc+ present with a higher frequency of ARID1A mutations and lack of EP300 mutations., Epidemiological studies have demonstrated the association between hepatitis B virus (HBV) infection and B-cell non–Hodgkin lymphoma (NHL), mainly for diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). We studied a cohort of 121 patients with FL for HBV infection status, clinical features, and gene mutational profile. Anti-HBc was detectable in 16 patients (13.2%), although all had undetectable HBV DNA. Anti-HBcore+ (anti-HBc+) cases presented with older age at diagnosis than anti-HBc− cases (68.1 vs 57.2 years; P = .007) and higher β2-microglobulin (56.3% vs 28.9%; P = .04). All patients included in the study fulfilled criteria for treatment and received therapy with rituximab or rituximab-containing chemotherapy. There were no episodes of HBV reactivation or HBV hepatitis during treatment and/or maintenance. Remarkably, anti-HBc+ patients had significantly lower 10-year progression-free survival (PFS; 12.9% vs 58.3%; P < .0001) and overall survival (OS; 22.0% vs 86.2%; P < .0001), that remained at multivariate analysis. Gene mutational profiling of all cases showed that anti-HBc+ cases had higher incidence of ARID1A mutations and absence of EP300 mutations, 2 key epigenetic regulators in FL. Overall, our study shows that FL patients with resolved HBV infection have a worse outcome independently of other well-known clinical risk factors and a distinct gene mutational profile.

Key Points 5-hydroxymethylcytosine and TET2 messenger RNA (mRNA) downregulation are common in myelodysplastic syndromes irrespective of TET2 mutations.TET3 mRNA expression levels are associated with distinct clinical outcomes in myelodysplastic syndromes with and without TET2 mutations., Decrease in DNA dioxygenase activity generated by TET2 gene family is crucial in myelodysplastic syndromes (MDS). The general downregulation of 5-hydroxymethylcytosine (5-hmC) argues for a role of DNA demethylation in MDS beyond TET2 mutations, which albeit frequent, do not convey any prognostic significance. We investigated TETs expression to identify factors which can modulate the impact of mutations and thus 5-hmC levels on clinical phenotypes and prognosis of MDS patients. DNA/RNA-sequencing and 5-hmC data were collected from 1665 patients with MDS and 91 controls. Irrespective of mutations, a significant fraction of MDS patients exhibited lower TET2 expression, whereas 5-hmC levels were not uniformly decreased. In searching for factors explaining compensatory mechanisms, we discovered that TET3 was upregulated in MDS and inversely correlated with TET2 expression in wild-type cases. Although TET2 was reduced across all age groups, TET3 levels were increased in a likely feedback mechanism induced by TET2 dysfunction. This inverse relationship of TET2 and TET3 expression also corresponded to the expression of L-2-hydroxyglutarate dehydrogenase, involved in agonist/antagonist substrate metabolism. Importantly, elevated TET3 levels influenced the clinical phenotype of TET2 deficiency whereby the lack of compensation by TET3 (low TET3 expression) was associated with poor outcomes of TET2 mutant carriers.