Multiple myeloma (MM) is a complex hematological malignancy characterized by genomic changes and transcriptomic dysregulation. Initial exome sequencing approaches have failed to identify any single, frequent (>25%) mutation in the coding genome. However, using whole-genome sequencing, we found that one of the genomic regions most frequently mutated (62% of the patients with MM) was the 5' untranslated region and/or intron 1 of the BCL7A gene. RNA-sequencing data from a large cohort suggest a loss of BCL7A expression in a large majority of patients with MM as compared with normal plasma cells. BCL7A loss of function in a panel of MM cell lines led to a highly proliferative phenotype in vitro and in vivo, whereas its ectopic expression significantly reduced cell viability, suggesting a tumor suppressor function for BCL7A in MM. We studied the cellular and molecular effects of BCL7A loss and observed that it endows myeloma cells with proliferative potential in cooperation with the plasma cell-defining transcription factor IRF4. BCL7A is involved in a direct protein-protein interaction with IRF4, limiting its DNA-binding activity. Loss of BCL7A thus enhances the expression of IRF4-associated cytokines and reduces mitochondrial metabolism and reactive oxygen species levels. Our study therefore suggests that BCL7A loss provides the necessary molecular change to allow IRF4-mediated transcriptional activity and MM cell growth and survival.

Relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) remains a challenging disease with dismal prognosis. Despite the revolutionary impact of CD19-directed chimeric antigen receptor (CAR19) T-cell therapy, >50% of patients relapse within a year. Both leukemia cell-intrinsic factors favoring immune escape and poor CAR T-cell persistence contribute to clinical failure. Moreover, the expression of immune checkpoint receptors (ICRs) and their ligands within the bone marrow (BM) microenvironment may contribute to leukemia progression and therapy resistance. Here, we characterized the expression of ICRs and their ligands in leukemic blasts, T cells, and mesenchymal stromal cells (MSCs) from B-ALL BM samples at diagnosis and relapse, comparing them with age-matched healthy BM controls. Our findings reveal a significantly upregulated expression of TIM-3 in T cells and its ligand, galectin-9, in both blasts and MSCs throughout disease progression. The expression of galectin-9 in B-ALL blasts and TIM-3 in CAR19 T cells negatively correlates with clinical outcome. Furthermore, we demonstrate that galectin-9 impairs CAR19 T-cell homeostasis and cytotoxicity. Notably, an engineered TIM-3-Fc decoy receptor, delivered either by primary T cells coadministered with CAR19 T cells or via a bicistronic all-in-one CAR19-TIM-3-Fc construct, improved the antileukemia efficacy and persistence of CAR19 T cells in B-ALL xenograft models. Mechanistically, CAR19-TIM-3-Fc T-cell treatment promotes the in vivo expansion of transduced and bystander effector and memory T cells, as determined by spectral flow cytometry. Collectively, these TIM-3-Fc decoy-armored CAR19 T cells offer a promising therapeutic strategy for patients with R/R B-ALL.

Cytokine release syndrome (CRS) and immune effector cell (IEC)-associated neurotoxicity syndrome (ICANS) are common complications after IEC therapy for hematologic malignancies. This 2-part phase 2 study (INCB 39110-211) investigated the safety and efficacy of itacitinib, a potent, highly selective Janus kinase 1 inhibitor with broad anti-inflammatory activity, for the prevention of CRS and ICANS in patients who received commercial CD19-directed IEC therapy. Patients in part 1 received 200 mg itacitinib once daily 3 days before IEC therapy (axicabtagene ciloleucel [axi-cel], brexucabtagene autoleucel, or tisagenlecleucel) through day 26 with guidelines for use of other CRS/ICANS interventions. In part 2 (double-blind), patients were randomized to receive 200 mg itacitinib twice daily or placebo 3 days before IEC therapy with axi-cel. The primary end point was the proportion of patients with CRS grade ≥2 by day 14 using the American Society for Transplantation and Cellular Therapy consensus grading system. Overall, 111 patients were enrolled (63 in part 1; 48 in part 2); 109 patients were analyzed for efficacy and 110 for safety. By day 14, grade ≥2 CRS occurred in fewer patients on 200 mg twice daily itacitinib (17.4%) than on placebo (56.5%; P = .003). The proportion of patients with grade ≥2 ICANS by day 28 was lower than with placebo (8.7% vs 21.7%). Itacitinib was well tolerated, with pyrexia being the most common treatment-emergent adverse event (200 mg itacitinib twice daily, 43.5%; placebo, 50.0%), and itacitinib-related cytopenias were manageable. Itacitinib did not affect IEC therapy efficacy (objective response rate at 6 months, 39.1% [200 mg itacitinib twice daily] vs 26.1% [placebo]). This study was registered at www.clinicaltrials.gov as #NCT04071366.

This study identified an increased risk of lymphoid malignancy in Shwachman-Diamond syndrome (SDS) with an observed risk 38-fold higher than expected based on population data. Increased toxicity was observed with standard therapies in patients with SDS.

The Csa blood group antigen was identified >50 years ago, but its genetic basis has yet to be elucidated. All our recent genomic investigation has failed to resolve the genetic basis of this enigmatic antigen. By investigating the association of the human neutrophil antigen (HNA)-3a/b polymorphism (rs2288904-G/A) in SLC44A2 with clinical features of sickle cell disease, we incidentally discovered that rare subjects with the homozygous HNA-3b/b genotype also carry the uncommon Cs(a-) phenotype. We genotyped this single-nucleotide polymorphism in a cohort of 25 Cs(a-) subjects and found that all of them showed an HNA-3b/b genotype. This result suggests that the high-prevalence allele with rs2288904 (HNA-3a; 455G) encoding Arg152 encodes the high-prevalence Csa. Accordingly, anti-Csa does not react with solute carrier (SLC)44A2null red blood cells (RBCs), SLC44A2 knockout K562 cells, and K562 cells expressing HNA-3b, confirming that the Csa and Csb antigens are carried on this protein. Furthermore, mass spectrometry analysis of SLC44A2 from neutrophils and RBCs, along with serological investigation, showed that, despite HNA-3a and Csa having the same genetic basis, anti-HNA-3a and anti-Csa recognize different epitopes on the SLC44A2 protein. Overall, our data resolve the genetic bases of the Cs(a-) and Cs(b-) blood phenotypes, with new insights on the anti-HNA-3a specificity.

Congenital thrombotic thrombocytopenic purpura (cTTP) is an ultrarare disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, and ischemic organ damage caused by pathogenic ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) variants. ADAMTS13-containing product, including fresh-frozen plasma (FFP), and plasma-derived factor VIII concentrates are commonly used to supply ADAMTS13; however, frequent hospital visits and allergic reactions are major drawbacks. A recombinant ADAMTS13 (rADAMTS13) was recently developed to address these issues. However, real-world evidence has not been reported owing to the rarity of this condition. This study compared the efficacy and safety of FFP and rADAMTS13 in 14 Japanese patients, including 5 patients with end-stage renal disease who were excluded from the phase 3 trial. The median peak level of ADAMTS13 activity 15 minutes after rADAMTS13 administration was significantly higher than that after FFP (68.4% vs 15.9%; P < .001). ADAMTS13 activity 1 week after rADAMTS13 administration was well maintained compared with FFP infusion (11.6% vs 5.1%; P < .001). Patients reported no allergic reactions after rADAMTS13 administration and appreciated the convenience of a single infusion of rADAMTS13, suggesting that rADAMTS13 is a safe and effective alternative to FFP in patients with cTTP. To our knowledge, this is the first publication of patients with cTTP who switched FFP to novel rADAMTS13 from Japanese real-world data.

Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome, and the overall survival (OS) of adult patients is poor. Ruxolitinib, a Janus kinase 1/2 (JAK1/2) inhibitor, has shown promise in treating HLH and exerts synergistic effects when combined with dexamethasone. Our pilot study preliminarily demonstrated that the combination of ruxolitinib and dexamethasone (Ru-D regimen) had a high response rate and led to favorable short-term survival outcomes in adult patients with HLH. In this prospective phase 2 clinical trial, we propose the Ru-D regimen as a first-line treatment for adults newly diagnosed as having HLH with unknown triggers. A total of 28 Chinese patients were enrolled, and the median follow-up time was 25.1 months (range, 0.87-34.0). The 2-month OS rate (the primary end point) was 85.7%, which exceeded our expected 2-month OS rate of 75%. The 6-month and 2-year OS rates were 67.9% (19/28) and 53.6% (15/28), respectively. The median OS of patients with lymphoma-associated HLH (LAHS) was 5.8 months, and most of these patients had natural killer/T-cell lymphoma. In contrast, the 2-year OS rate of patients without LAHS was 75%. The overall response rate was 85.7% (24/28); of 28 patients, 5 (17.9%) achieved a complete response during the Ru-D regimen. Overall, the Ru-D regimen was well tolerated in patients with HLH. This study demonstrates the efficacy and safety of the Ru-D regimen in adults newly diagnosed as having HLH with unknown triggers and warrants a phase 3 randomized controlled study. This trial was registered at www.chictr.org.cn as #ChiCTR2100049996).

Genetic screening for severe congenital immunohematological diseases offers potential for early intervention, particularly through preemptive allogeneic hematopoietic stem cell transplantation (HSCT). However, the clinical value of such screening depends on precise prognostic predictions based on genotype-phenotype correlations and/or functional confirmation. We investigated familial hemophagocytic lymphohistiocytosis type 2 (FHL2), caused by PRF1 variants. Specifically, we evaluated the clinical significance of the frequent PRF1 A91V variant, if present in trans with a predicted loss-of-function (pLOF) PRF1 variant, defined as "disease mutation" listed in the Human Gene Mutation Database. We combined clinical and functional data from our hemophagocytic lymphohistiocytosis (HLH)-network registry with UK Biobank data to evaluate disease penetrance and clinical outcomes. Among 52 individuals with A91V/pLOF genotype in the registry, 39 (72%) showed FHL2-related manifestations with mean onset at 20 years. Four patients had recurrent disease, 15 received transplantation, and 14 died. Among 14 individuals with A91V/pLOF genotype identified by family screening (mean age, 29 years), however, only 1 was symptomatic. Moreover, among 21 A91V/pLOF carriers identified in 200 000 UK Biobank participants, 12 with genotypes identical to symptomatic registry patients, none had developed HLH by age 73 years. Premature stop pLOF alleles appeared more penetrant than missense variants, but functional data including perforin expression or cytotoxicity failed to predict disease manifestation. Our combined registry and population-based approach reveals significant variability in disease penetrance and severity among PRF1 A91V/pLOF carriers, with no clear association between genotype, functional data, and clinical outcomes. This complexity illustrates the challenges of genetic screening and highlights the need for careful clinical decision-making regarding preemptive HSCT in asymptomatic carriers.

Follicular lymphoma (FL) represents a heterogeneous group of B-cell neoplasms with distinct genetic, epigenetic, microenvironmental, and clinical features. It is the most prevalent indolent non-Hodgkin lymphoma, characterized by a relapsing course and risk of transformation to aggressive diffuse large B-cell lymphoma. Recent advances in high-throughput sequencing, spatial transcriptomics, and imaging technologies uncovered genetic, epigenetic, and immunogenetic features underpinning FL, offering insights into its biology and potential therapeutic vulnerabilities. Although FL is primarily driven by the hallmark t(14;18) translocation involving BCL2, its pathogenesis requires additional oncogenic mutations, particularly in genes regulating chromatin and histone modifications. These early genetic and epigenetic alterations promote the persistence and evolution of cancer precursor cells, setting the stage for lymphomagenesis. The tumor microenvironment is also crucial in FL progression and patient prognosis, with T cells, stromal cells, and macrophages playing pivotal roles in facilitating tumor immune escape. Targeted therapies, including B-cell lymphoma 2 (BCL2) inhibitors, epigenetic modulators, and immunotherapies, have emerged from this deeper understanding of FL biology. Achieving a cure for FL will require targeted therapies that selectively eliminate cancer precursor cells with minimal impact on normal cells, thus preventing relapse and avoiding harmful side effects. Eradicating minimal residual disease should be a primary objective rather than waiting for clinical relapse. Future research must prioritize the development of accurate experimental models, the elucidation of FL precursors, and a deeper understanding of its heterogeneity, dependencies, progression, and mechanisms driving transformation. Implementing targeted therapies at FL early stages, instead of the current "watch and wait" approach, will be essential to improve patient outcomes.

We report our single-center experience demonstrating that HLA class I alloimmunization predicts longer time to platelet engraftment, increased bleeding complications, and higher transfusion requirements in patients undergoing gene-modified hematopoietic stem cell transplant for transfusion-dependent β thalassemia.

Inherited bone marrow failure syndromes (IBMFS) are genetic disorders of impaired hematopoiesis that manifest in childhood with both cytopenias and extrahematologic findings. Although several IBMFS are categorized as ribosomopathies owing to shared underlying ribosomal dysfunction, there is a broader disruption of the protein homeostasis (proteostasis) network across both classic and emerging IBMFS. Precise regulation of the proteostasis network, including mechanisms of protein synthesis, folding, trafficking, and degradation and associated stress response pathways, has emerged as essential for maintaining hematopoietic stem cell function, providing new potential mechanistic insights into IBMFS pathogenesis. Furthermore, the varied clinical trajectories of patients with IBMFS with possible divergent outcomes of malignancy and spontaneous remission may reflect developmental and temporal changes in proteostasis activity and be driven by strong selective pressures to restore proteostasis. These new insights are spurring fresh therapeutic approaches to target proteostasis. Thus, further evaluation of proteostasis regulation and the consequences of proteostasis disruption in IBMFS could aid in developing new biomarkers, therapeutic agents, and preventive approaches for patients.

Type 1 plasminogen deficiency (PLGD), an ultrarare disorder caused by PLG pathogenic variants, results in decreased levels of immunoreactive and functional plasminogen. PLGD can cause fibrin-rich pseudomembranes on mucosa that impair tissue/organ function, affect quality of life, and are potentially life threatening. Lesion regression/resolution is facilitated by IV administration of human plasma-derived Glu-plasminogen (IV PLG concentrate), the first and only US Food and Drug Administration-approved specific treatment, licensed in 2021. The diagnosis of PLGD is frequently delayed because of its rarity (1.6 per million) and the variability of the initial medical specialty contact determined by the affected systems. Symptoms are often attributed to more common conditions, such as conjunctivitis, recurrent otitis media, reactive airway disease, etc. This article presents clinical vignettes highlighting strategies for PLGD diagnosis and treatment. Initial evaluation includes a detailed history, laboratory assays, and, at times, radiologic or other procedures. Genetic testing can confirm the diagnosis. Consistent, knowledgeable management is required to promptly identify and treat lesions, even in initially asymptomatic individuals. Personalized treatment may include continuous prophylaxis or intermittent treatment with IV PLG concentrate, dependent on disease severity and clinical course. Specialized facilities such as hemophilia treatment centers offering multidisciplinary care represent medical homes for this ultrarare disorder.

Paroxysmal nocturnal hemoglobinuria (PNH) is a nonmalignant clonal hematopoietic disorder. There are 2 components to the pathogenesis of PNH: (1) a mutant stem cell and (2) expansion of the mutant clone. Component 1 is straightforward: there is almost always an inactivating somatic mutation of the X-linked gene PIGA. As for component 2, different mechanisms may be involved. In rare cases, expansion may be driven by independently arisen mutations (eg, in JAK2); however, in most patients with PNH, such mutations are not found. Instead, clonal expansion may result from the escape of glycosylphosphatidylinositol (GPI)-negative (PIGA-mutant) stem cells from a T-cell-mediated autoimmune attack on nonmutant stem cells. Several lines of evidence support this mechanism. (1) PNH is closely related to aplastic anemia (AA). (2) PIGA-mutant microclones exist in normal people but they do not expand. (3) In patients with PNH receiving syngeneic bone marrow transplantation, PNH remission has occurred only when immunosuppressive conditioning was applied. (4) After targeted inactivation of piga in mice, large populations of GPI-negative blood cells are produced, but they gradually disappear rather than expand. (5) There is evidence that cytotoxic T cells may spare GPI-negative stem cells, and CD1d-restricted GPI-specific T cells have been demonstrated in patients with PNH and with AA. Thus, the pathogenesis of PNH conforms to a Darwinian model within somatic cell populations: it results from a somatic mutation and a specific selective environment. The findings in PNH are also highly relevant to the pathogenesis of AA.

The critical role of leukemia-initiating cells as a therapy-resistant population in myeloid leukemia is well established. However, the molecular signatures of such cells in acute lymphoblastic leukemia remain underexplored. Moreover, their role in therapy response and patient prognosis is yet to be systematically investigated across various types of acute leukemia. We used single-cell multiomics to analyze diagnostic specimens from 96 pediatric patients with acute lymphoblastic, myeloid, and lineage-ambiguous leukemias. Through the integration of single-cell multiomics with extensive bulk RNA sequencing and clinical data sets, we uncovered a prevalent, chemotherapy-resistant subpopulation that resembles hematopoietic stem and progenitor cells (HSPC-like) and is associated with poor clinical outcomes across all subtypes investigated. We identified a core transcriptional regulatory network (TRN) in HSPC-like blasts that is combinatorially controlled by HOXA/AP1/CEBPA. This TRN signature can predict chemotherapy response and long-term clinical outcomes. We identified shared potential therapeutic targets against HSPC-like blasts, including FLT3, BCL2, and the PI3K pathway. Our study provides a framework for linking intratumoral heterogeneity with therapy response, patient outcomes, and the discovery of new therapeutic targets for pediatric acute leukemias.