We comprehensively profiled the landscape of immunoglobulin (IG) and T-cell receptor (TR) rearrangements at diagnosis in 1212 patients with acute lymphoblastic leukemia (ALL; 573 children and 639 adults) diagnosed in Germany between 2017 and 2022. Our study revealed a significant age-related decrease in immunogenetic maturation, where IG κ rearrangements in B-ALL and complete TR β/δ rearrangements in T-ALL, hallmarks of maturity, were more frequent in pediatric patients compared to adults (B-ALL: 68.7% vs 39.0%, P < 2.2e-16; T-ALL: 85.7% vs 67.3%, P = 6.7e-03). Compared to adults, children had a higher average number of IG/TR markers per patient (6 vs 4; P = 2.5e-38) and markedly fewer lacked these markers (0.5% compared to 6.7%). IG heavy chain clonal evolution was most pronounced among pro-B-ALL cases (60.9%), with the V-to-DJ mechanism driving pro-B evolution (78.6%), whereas V-replacement dominated other immunophenotypes. Furthermore, expanded accompanying T-cell clones of unknown significance in B-ALL increased with age. This next-generation sequencing-based study offers an unprecedented characterization of IG/TR rearrangement patterns across ALL subtypes and age groups. It highlights the higher immunogenetic maturity in children, which may be explained by the infection-driven abnormal activity of the IG/TR recombination machinery in pediatric ALL.

Hemorrhage causes millions of deaths and hundreds of billions of dollars in medical costs every year, and a large percentage of trauma bleeding associated deaths occur in the pre-hospital setting. Bleeding is typically treated with transfused blood products, but this is difficult in the prehospital setting due to limitations in transportation and storage, especially in rural and remote military settings. Advancements in cold-stored platelets and lyophilized blood products have the potential to address some of these limitations. However, devising novel products that continue to improve shelf life, portability, scalability, cost, and safety for patients experiencing bleeding in pre-hospital settings could greatly improve treatment options and patient outcomes. This review primarily focuses on rationale design of material-based approaches to develop novel hemostatic agents that strive to meet limitations of current blood products, especially for use in the pre-hospital setting. Key topics of consideration include how material design can lead to identification of effective therapies that stop bleeding as well as strategies to iterate on existing designs to enhance healing after cessation of bleeding. Improving performance and functionality of existing and emerging materials could be achieved through the incorporation of transglutaminases, growth factors, cellular components, or inorganic molecules. Finally, consideration of patient specific factors that influence bleeding, such as patient sex and age, through evaluation of therapies in specific populations and/or design of materials targeted for specific patient populations is a key area for development of next generation hemostatic materials.

Heparin-induced thrombocytopenia (HIT) is initiated by antibodies that recognize large antigenic complexes composed of multiple molecules of cationic platelet factor 4 (PF4) and polyanions such as unfractionated heparin (UFH) that bind to each other primarily through electrostatic interactions. We asked whether the formation and stability of these HIT antigenic or ultralarge immune complexes (ULICs) would be inhibited by biocompatible synthetic polycationic molecules shown previously to dissociate UFH from antithrombin III and to inhibit polyphosphates. Members of this family of molecules, designated universal heparin reversal agents (UHRAs), inhibited formation and dissociated preformed ultralarge PF4-UFH (antigenic) complexes (ULCs), dissociated ULICs composed of the HIT-like monoclonal antibody KKO and ULCs, blocked binding of human HIT immunoglobulin G antibodies to PF4/heparin, binding of KKO to platelets, KKO-induced adhesion of platelets to activated human endothelium under flow, and microvascular thrombosis induced by KKO in a mouse model of HIT. These data suggest that UHRAs might provide a rationale intervention that acts at an early step in the pathogenesis of HIT to enhance the benefits and lessen the risks of nonheparin anticoagulants. Destabilization of immune complexes using polycationic inhibitors might also find a role in management of other polyanion PF4-antibody-mediated conditions, including vaccine-induced thrombocytopenia/thrombosis, postviral, and autoimmune HIT.

Hematopoietic stem cells (HSCs) exhibit significant age-related phenotypic and functional alterations. Although single-cell technologies have elucidated age-related compositional changes, prospective identification of aging-associated HSC subsets has remained challenging. In this study, using clusterin (Clu)-green fluorescent protein (GFP) reporter mice, we demonstrated that Clu expression faithfully marks age-associated myeloid/platelet-biased HSCs throughout life. Clu-GFP expression clearly segregates a novel age-associated HSC subset that overlaps with but is distinct from those previously identified using antibodies against aging maker proteins or reporter systems of aged HSC signature genes. Clu-positive (Clu+) HSCs emerge as a minor population in the fetus and progressively expand with age. Clu+ HSCs display not only an increased propensity for myeloid/platelet-biased differentiation but also a unique behavior in the bone marrow, favoring self-renewal over differentiation into downstream progenitors. In contrast, Clu-negative (Clu-) HSCs exhibit lineage-balanced differentiation, which predominates in the HSC pool during development but becomes underrepresented as aging progresses. Both subsets maintain long-term self-renewal capabilities even in aged mice but contribute differently to hematopoiesis. The predominant expansion of Clu+ HSCs largely drives the age-related changes observed in the HSC pool. Conversely, Clu- HSCs preserve youthful functionality and molecular characteristics into old age. Consequently, progressive changes in the balance between Clu+ and Clu- HSC subsets account for HSC aging. Our findings establish Clu as a novel marker for identifying aging-associated changes in HSCs and provide a new approach that enables lifelong tracking of the HSC aging process.

Previous results from CASSIOPEIA demonstrated superior progression-free survival (PFS) and minimal residual disease (MRD) negativity with the addition of daratumumab to bortezomib, thalidomide, and dexamethasone (VTd) induction/consolidation and with daratumumab maintenance vs observation in transplant-eligible, newly diagnosed multiple myeloma. Here, we present long-term MRD status and PFS outcomes after a median follow-up of 80.1 months. Patients were randomly assigned (1:1) to daratumumab plus VTd (D-VTd) or VTd induction/consolidation; patients remaining on study were rerandomized to daratumumab maintenance or observation for ≤2 years. MRD status was assessed at predefined time points during each study phase. D-VTd improved overall MRD-negativity rates (10-5) after induction (34.6% vs 23.1%) and consolidation (63.7% vs 43.7%) and provided PFS benefit, regardless of postinduction MRD status, vs VTd alone. Daratumumab maintenance improved overall MRD-negativity rates over observation, regardless of induction/consolidation treatment (D-VTd/daratumumab vs D-VTd/observation, 10-5 [77.3% vs 70.7%] and 10-6 [60.7% vs 52.0%]; VTd/daratumumab vs VTd/observation, 10-5 [70.9% vs 51.2%] and 10-6 [48.4% vs 30.7%]) and improved MRD-negativity rates, regardless of risk status, as defined by cytogenetic abnormalities or the revised International Staging System score. Furthermore, daratumumab maintenance provided PFS benefit vs observation, regardless of induction/consolidation treatment and postconsolidation MRD status. D-VTd followed by daratumumab maintenance consistently produced the highest landmark, cumulative, and sustained MRD-negativity rates (10-5 and 10-6), translating to superior long-term PFS outcomes. These results demonstrate that daratumumab-based induction/consolidation followed by daratumumab maintenance resulted in the deepest and most durable MRD negativity, leading to superior PFS outcomes. This trial was registered at www.clinicaltrials.gov as #NCT02541383.

Multiple myeloma (MM) initiation is dictated by genomic events. However, its progression from asymptomatic stages to an aggressive disease that ultimately fails to respond to treatments is also dependent on changes of the tumor microenvironment (TME). Clonal hematopoiesis of indeterminate potential (CHIP) is a prevalent clonal condition of the hematopoietic stem cell whose presence is causally linked to a more inflamed microenvironment. Here, we demonstrate in 106 patients with MM that CHIP is frequently coexisting with MM at diagnosis, associates with a more advanced Revised International Staging System stage and higher age, and has a nonsignificant trend toward lower median hemoglobin. In our cohort, the 2 conditions do not share a clonal origin. Single-cell RNA sequencing in 16 patients with MM highlights significant TME changes when CHIP is present: decreased naive T cells, a proinflammatory TME, decreased antigen-presenting function by dendritic cells, and expression of exhaustion markers in CD8 cells. Inferred interactions between cell types in CHIP-positive TME suggested that especially monocytes, T cells, and clonal plasma cells may have a prominent role in mediating inflammation, immune evasion, and pro-survival signals in favor of MM cells. Altogether, our data reveal that, in the presence of CHIP, the TME of MM at diagnosis is significantly disrupted in line with what is usually found in more advanced disease, with potential translational implications. Our data highlight the relevance of this association and prompt for further studies on the modifier role of CHIP in the MM TME.

We observed diabetes mellitus (DM) in 9.3% of adults with sickle cell disease (SCD), and DM predicted a sevenfold greater risk of chronic kidney disease progression adjusting for high-risk APOL1. Our results emphasize the clinical significance of DM in SCD.

"Nonclassical" myeloproliferative neoplasms (MPNs) and myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) represent a heterogeneous group of malignancies characterized by a wide range of clinical manifestations. Unlike classical MPNs, there is no standardized management approach for these conditions, particularly concerning the indications for and management of allogeneic hematopoietic cell transplantation. To address this gap, the European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonization and Guidelines (PH&G) Committee and the Chronic Malignancies Working Party (CMWP) have collaborated to develop shared guidelines aimed at optimizing the selection and management of patients with these rare forms of neoplasms. A comprehensive review of the literature from the publication of the revised fourth edition of the (2016) World Health Organization classification onward was conducted. A multidisciplinary group of experts in the field convened to produce this document, which was developed through multiple rounds of draft circulation. Key recommendations include the early identification of potential transplant candidates, particularly in cases of chronic neutrophilic leukemia, chronic eosinophilic leukemia (CEL)/CEL, not otherwise specified (CEL-NOS), myeloid/lymphoid neoplasm with eosinophilia and tyrosine kinase gene fusions with FGFR1, JAK2, ABL1, and FLT3 rearrangements, MDS/MPN with neutrophilia/atypical chronic myeloid leukemia, and MDS/MPN, NOS. For patients with MPN, NOS/MPN unclassifiable, standard recommendations for myelofibrosis should be applied. Similarly, in MDS/MPN with thrombocytosis, transplantation is recommended on the basis of established MDS guidelines. Given the current lack of robust evidence, this document will serve as a valuable resource to guide future research activities, providing a framework for addressing critical unanswered questions and advancing the field.

Despite recent advances in graft-versus-host disease (GVHD) prophylaxis, novel approaches to effective prevention of chronic GVHD (cGVHD) remain of high importance. In this prospective, multicenter, phase 2 trial, ruxolitinib, an oral inhibitor of Janus kinase (JAK) 1 and 2, was administered as maintenance therapy after reduced-intensity allogeneic hematopoietic cell transplantation (HCT). GVHD prophylaxis consisted of tacrolimus and methotrexate. Ruxolitinib began between day +30 to 100 and was administered continuously in 28-day cycles for up to 24 cycles. Seventy-eight participants were enrolled before HCT; 63 participants received the intervention. The median start date of ruxolitinib after HCT was day +45. The most common grade ≥3 adverse events were neutropenia, thrombocytopenia, and anemia. Seven participants experienced grade ≥3 infectious events. GVHD-free, relapse-free survival at 1 year after HCT, the primary end point, was 70%. Grade 3 to 4 acute GVHD at 6 months was 4.8%, and moderate-severe cGVHD at 2 years was 16%. cGVHD requiring systemic therapy was 9.5% at 1 year and 13% at 2 years. Overall survival and progression-free survival at 2 years were 76% and 68%, respectively. Prolonged administration of ruxolitinib following HCT is associated with low rates of clinically significant cGVHD. The incorporation of JAK inhibition into GVHD prevention approaches warrants further investigation. This trial was registered at www.clinicaltrials.gov as #NCT03286530.

Phosphoinositide 3-kinase gamma (PI3Kγ), the only class IB PI3 kinase, is a cell-extrinsic immunotherapy target in solid tumors. PI3Kγ inhibition reprograms immunosuppressive myeloid cells to acquire immunostimulatory phenotypes, which promote antitumor cytotoxic T-cell activity. Although PI3Kγ inhibition has no direct effect on solid tumor cells, several new studies have nominated PI3Kγ as a cell-intrinsic target in various leukemias, particularly acute myeloid leukemia. Intrinsic dependency on PI3Kγ is present at baseline in leukemias with specific pathological characteristics, is inducible by extrinsic inflammation in others, and may also be acquired with resistance to certain therapies. The discovery of leukemia PI3Kγ dependency has generated enthusiasm for immediate clinical trial evaluation of inhibitor monotherapy and combinations. Parallel laboratory evaluation is needed to develop an improved understanding of leukemia disease features associated with clinical inhibitor sensitivity that might suggest biomarker-directed patient enrichment strategies. In this review, we discuss recent progress credentialing PI3Kγ as a bona fide target in leukemia. We also highlight open questions, including a need to understand the mechanism of acquired resistance to PI3Kγ inhibition, how to optimally prioritize combination therapies to enhance PI3Kγ inhibitor utility, and how cell-extrinsic effects of PI3Kγ inhibition in the leukemia microenvironment might also contribute to clinical activity.

Emerging evidence indicates that CD4+ T cells contribute to antitumor immunity beyond their traditional roles as helpers or regulators. However, the specific subset of CD4+ T cells mediating beneficial outcomes in patients with multiple myeloma remains unclear. Here, we performed single-cell RNA sequencing and T-cell receptor sequencing on CD4+ T cells sorted from the bone marrow of patients across the stages of myeloma progression. We identified several distinct states of CD4+ cytotoxic T lymphocytes (CTLs) that were significantly increased and clonally expanded in patients with myeloma. CD4+ CTLs displayed transcriptional and phenotypic characteristics indicative of cytotoxicity, demonstrating their ability to directly kill myeloma cells. This cytotoxicity, however, was abrogated by NKG2D blockade. Notably, the abundance of NKG2D+CD4+ CTLs correlated with improved survival in patients with myeloma. Our findings suggest that harnessing CD4+ CTLs could lead to novel strategies for enhancing immunotherapy outcomes in multiple myeloma.

The half-life of recombinant human von Willebrand factor (rVWF) expressed in CHO cells (CHO-rVWF; Vonicog alfa; and Vonvendi/Veyvondi) is significantly longer than that of plasma-derived VWF (pdVWF). This finding is intriguing because CHO cells do not generate α2-6 sialylation, which constitutes the majority of human pdVWF sialylation. We hypothesized that glycan differences might regulate the longer half-life of CHO-rVWF. In lectin plate-binding assays and liquid chromatography-mass spectrometry analysis, we confirmed that CHO-rVWF lacked α2-6-linked sialylation. Conversely, however, α2-3-linked sialylation was significantly increased on CHO-rVWF, which also had reduced exposed β-galactose (β-Gal) compared to pdVWF. Consistent with human data, CHO-rVWF clearance was significantly (P < .001) reduced in VWF-/- mice compared to pdVWF. However, clearance of asialo-pdVWF and asialo-CHO-rVWF were identical. In keeping with the in vivo half-life prolongation, CHO-rVWF binding to murine macrophages (P = .012) and HepG2 cells (P = .001) was significantly decreased compared to pdVWF. Furthermore, CHO-rVWF binding to purified macrophage-galactose-type lectin (MGL) receptor and asialoglycoprotein receptor (ASGPR) was also significantly reduced. In contrast to pdVWF, in vivo studies in MGL1-/- mice and Asgr1-/- mice demonstrated that neither MGL nor ASGPR plays significant roles in regulating CHO-rVWF clearance. Together, our findings demonstrate that enhanced α2-3-linked sialylation on CHO-rVWF is responsible for its extended half-life.

We used single-cell genomics to characterize a patient with T-cell acute lymphoblastic leukemia treated in the Children's Oncology Group AALL0434 trial with poor clinical outcome despite favorable genomic features, identifying a STAT1-mediated interferon-related transcriptional signature and inflammatory microenvironment associated with sensitivity to small-molecule JAK inhibition.