HemaSphere最新文献

Diamond–Blackfan anemia (DBA) is a rare bone marrow failure syndrome accompanied by cardiovascular, skeletal, and urogenital abnormalities. Most of the affected individuals carry mutations in ribosomal proteins, including RPS19, a component of the 40S ribosomal subunit. We developed a transgenic Rps19 mouse model harboring a deletion of conserved R67 that displays a variable phenotype ranging from mild hematopoietic defects to severe anemia and a set of other skeletal, muscular, and cardiac abnormalities with shorter survival. This mouse model exhibited an activation of the p53 signaling pathway in red blood cell committed hematopoietic stem and progenitor cells, affecting erythroid lineage development. Competitive transplantation assays using Rps19^R67∆ bone marrow progenitor cells confirmed that short-term repopulating hematopoietic stem cells (HSCs) and their progenitor lineages were affected, while their differentiation was rescued after deletion of the tumor suppressor Trp53. Rps19^R67∆ mutation leads to pre-ribosomal RNA (pre-rRNA) accumulation coupled with activation of p53, even at relatively immature hematopoietic stages. In conclusion, we present a mouse model that represents a powerful tool for exploring new therapeutic options for the treatment of ribosomal disorders, including DBA.

Standard frontline treatment of chronic lymphocytic leukemia (CLL) is with fixed-duration venetoclax-based doublets or indefinite covalent Bruton tyrosine kinase inhibitor (BTKI). Although these approaches achieve excellent results, venetoclax doublets have diminished efficacy in high-risk biological subgroups, and indefinite covalent Bruton tyrosine kinase inhibitor (cBTKI) is associated with cumulative cardiovascular and infectious toxicity. Triplet regimens for treatment of CLL involve simultaneous use of cBTKI, venetoclax, and anti-CD20 monoclonal antibody. Three major frontline Phase 3 trials (CLL-13/GAIA, AMPLIFY, and A041702) have demonstrated higher rates of undetectable minimal residual disease (uMRD) and longer remissions with triplets than doublets, particularly in patients with IGHV-unmutated (IGHV-U) disease. However, this comes at the cost of increased infectious toxicity, particularly with COVID-19, and thus has translated into a variable impact on progression-free survival (PFS) and, to-date, no overall survival (OS) benefit. Although there are promising Phase 2 data for triplets in patients with TP53 aberrant or relapsed disease, the heterogeneity of treatment duration/MRD definition, lack of control arm, and potential increased toxicity make it premature to use triplets in these groups. We recommend considering triplets in treatment naïve CLL patients with IGHV-U, TP53 wild type, anticipated low incidence/good tolerance of Gr ≥ 3 infection (<70 years old, no major comorbidity and fully immunized) who are well informed and prioritize maximal time off therapy at the expense of increased short-term logistical complexity. Future triplet research should focus on randomized trials in specific genomic subgroups, incorporating novel agents (e.g., non-covalent BTKI, BTK degrader, and next-generation BCL2 inhibitors) and new ways of adapting treatment duration to maximize efficacy and minimize toxicity.

Large B-cell lymphoma (LBCL) with IRF4 rearrangement (LBCL-IRF4-R) is a rare subtype predominantly diagnosed in children and young adults. Whether adult LBCL cases with IRF4 rearrangement (IRF4-R) should be classified as LBCL-IRF4-R remains unclear. Clinicopathological and molecular features of 61 adult LBCL cases with IRF4-R were analyzed and compared to diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), to assess biological heterogeneity. The 61 cases grouped by patient age and site were classified as follows: Group 1 included 13 patients aged ≤40 years, whose features supported LBCL-IRF4-R, showing favorable outcomes with high frequencies of IGH::IRF4 fusion and IRF4 mutations. Group 2 comprised 37 patients aged >40 years with tumors at usual sites; 17 early-stage cases largely retained LBCL-IRF4-R characteristics, whereas three other early-stage cases showed molecular or clinical features more consistent with DLBCL, NOS with IRF4-R. Twelve advanced-stage cases showed aggressive behavior with adverse DLBCL, NOS-associated mutations (e.g., TP53), suggesting classification as follicular lymphoma grade 3A (FL-3A) and DLBCL with IRF4-R or DLBCL, NOS with IRF4-R. Five cases lacked sufficient data for definitive classification. Group 3 included 11 patients aged >40 years with tumors at unusual extranodal sites; except for one case classified as LBCL-IRF4-R, the remaining 10 cases showed aggressive clinical behavior with frequent MYD88 mutations, favoring classification as FL-3A and DLBCL with IRF4-R or DLBCL, NOS with IRF4-R. These findings support a multidimensional approach that integrates age, tumor site, and clinicomolecular features to refine classification, enhance risk stratification, and guide personalized management in adult LBCL cases with IRF4-R.

In AML with 3q26.2 rearrangements (r) the distal GATA2 hematopoietic enhancer becomes aberrantly relocated leading to activation of EVI1 expression. EVI1 is a transcriptional regulator that plays a role in proliferation and maintenance of a stem cell-like phenotype in AML. BRG1 (SMARCA4) and BRM (SMARCA2) are the mutually exclusive ATPases of the BAF (BRG1/BRM-associated factor) chromatin remodeling complexes. They regulate access to enhancers/promoters and gene-expressions orchestrating AML stem/progenitor cell proliferation and differentiation. AML with 3q26.2 rearrangements are clinically challenging and prognosis remains very poor. FHD-286 is an orally bioavailable, selective inhibitor of BRG1/BRM under clinical development in AML. Present studies show that FHD-286 induced differentiation and lethality in AML cells with MECOM-r, perturbed chromatin accessibility and depleted expression of EVI1, c-Myc, CD44 and CDK4. Co-treatment with FHD-286 and decitabine, BET inhibitor (BETi) or HAT inhibitor synergistically induced in vitro lethality in patient-derived AML cells with MECOM-r. In patient-derived xenograft (PDX) models of AML with MECOM-r, compared to each drug alone, co-treatment with FHD-286 and BETi OTX015 significantly reduced AML burden and improved survival, without inducing significant toxicity. These findings highlight the FHD-286-based combinations as promising therapy of AML with chromosome 3q26.2 rearrangement and EVI1 overexpression.

The germinal center (GC) reaction is essential for orchestrating humoral immunity by producing plasma cells (PCs) and memory B cells (MBCs). TET2, an α-ketoglutarate-dependent dioxygenase, plays a critical role in B-cell exit from the GC and in plasma cell differentiation. Moreover, TET2 functions as a tumor suppressor in diffuse large B-cell lymphoma (DLBCL), with mutations frequently observed in the ST2 DLBCL subgroup, which is marked by elevated NF-κB and PI3K signaling and predominant expression of IgG B-cell receptors (BCRs). We used a combination of in vivo mouse models and in vitro differentiation systems to investigate the effects of Tet2 deficiency on IgG1+ GC B-cells. We performed flow cytometry, gene expression, and DNA methylation analysis to assess differentiation, proliferation, and molecular alterations. Tet2-deficient IgG1+ GC B-cells displayed impaired differentiation into both PCs and MBCs, accompanied by enhanced proliferation. These cells exhibited hypermethylation and repression of the Nfkbia locus, increased activation of the NF-κB subunit c-Rel, and sustained high levels of surface IgG1. Upon recall immunization, Tet2-deficient IgG1+ MBCs failed to efficiently differentiate into PCs, resulting in their accumulation and further GC expansion. These findings demonstrate that Tet2 is essential for balancing proliferation and terminal differentiation of IgG1+ GC B-cells during the humoral response. The impaired regulation of this balance due to Tet2 loss provides mechanistic insight into a contributory pathway that may facilitate DLBCL transformation in TET2-mutated cases.

We applied supervised and unsupervised machine learning (ML) analyses to a cohort of 140 patients referred to the Hematology Unit of the G. Gaslini Institute from 1989 to 2023 for persistent cytopenia and/or features suggestive of telomere biology disorders (TBDs). Patients were labeled as “TBD” (n = 20, established molecular diagnosis of TBD), “other diagnosis” (OD, n = 27, established molecular diagnosis of congenital disease including marrow failures), and “undefined diagnosis” (UD, n = 93, no established molecular diagnosis). After training a random forest model on 47 patients with established molecular diagnosis (20 TBD and 27 OD), supervised analysis was applied to the UD group and predicted 16/93 patients as having potential TBD and 77/93 subjects with potential OD, accounting for 17.2% and 82.7% of possibly reallocated diagnoses, respectively. The unsupervised approach applied to the whole cohort (n = 140) identified 4 distinct clusters to be significantly associated (P = 0.000001) with 47 molecular diagnoses, with TBD patients prevailing in Clusters 1 and 2 and OD patients in Clusters 3 and 4. Telomere length (TL) and mucocutaneous abnormalities were the most relevant drivers in discriminating between the TBD and OD groups in supervised and unsupervised analyses; they prevailed in Clusters 1 and 2. Interestingly, both analyses yielded similar results in the UD group, where all 16/93 patients without molecular diagnosis predicted to have TBD in the supervised approach were placed in “TBD clusters” 1–2 of the unsupervised analysis. This model might correctly reallocate a remarkable proportion of undefined or previously misclassified cases, thus potentially leading to substantially improved diagnostic work-up of rare and challenging diseases like TBD.

I read with interest the recent article from Johnstone et al., which eloquently set out the case for changing the diagnostic approach to chronic lymphocytic leukemia (CLL).¹ The first-hand account from co-author Peter Allen, a person living with CLL, is powerful and resonated strongly with me. Although the article is centered on just one person's story, the literature suggests that Peter's experience is representative.

Medical decision-making can often be distilled to the careful balancing of benefits and risks. In this context, there is a rationale for identifying individuals with CLL, both to monitor for disease progression and because of the significant risk of infection.²

However, our skill as clinicians is to tailor our counseling and advice to the person in front of us. Several years ago, when starting out as a hematology trainee in the laboratory, I would frequently intercept and send off the blood of patients with isolated, persistent lymphocytosis for flow cytometry. This was with the best of intentions—knowing that if I did so and asked for the patient to be referred to the hematology clinic, we could save some time and effort. I do not know how common this practice is, but from recent discussions, I suspect that it is not unusual. Nowadays, I am much more circumspect about my ability to harm people, to effectively ruin their lives with a flick of my pen.

What right do I have to perform these kinds of investigations without consent? What right do I have to diagnose someone with leukemia without affording them a careful explanation of the risks and benefits? Moreover, in what world is it okay for a person to come to hospital, meet a hematologist for the first time, and walk out with the label of “leukemia patient”?

The same is true of monoclonal gammopathy of undetermined significance (MGUS), another diagnosis that medicalizes normal aging, and one that also has a profound impact on quality of life.^{3, 4} How many of the people we see with MGUS have given true, informed consent for a test that could ruin their lives? Of course, it is not possible to ask patients to consent for every single test, but the bar for consent should be high.

My plea is that we all think long and hard about the harm that we can do and make sure that we give the people for whom we care an informed choice.

Richard J. Buka: Conceptualization; writing—original draft; writing—review and editing.

The author was a named applicant on a grant from AstraZeneca UK Limited, which was for work unrelated to this subject area.

Data sharing is not applicable to this article as no data sets were generated or analyzed during the current study.

The B-cell lymphoma 2 (BCL-2) inhibitor venetoclax (VEN) in combination with hypomethylating agents (HMAs) has improved treatment outcomes for acute myeloid leukemia (AML) patients unfit for intensive chemotherapy and is increasingly used in the relapsed/refractory setting. However, primary resistance remains a significant challenge, affecting 20%–35% of treatment-naïve and around 50% of previously treated AML patients. To investigate the mechanisms driving primary resistance to VEN–HMA therapy, we analyzed genetic, transcriptomic, BCL-2 family protein expression, and ex vivo drug sensitivity data from 101 AML patients and correlated these profiles with clinical outcomes to VEN–HMA. Our study found that blasts from refractory patients exhibit an elevated BCL-XL/BCL-2 protein expression ratio, an immature CD34⁺CD38⁻ phenotype, and frequent TP53 mutations. Consistent with the high ratio of BCL-XL/BCL-2, resistant samples showed increased ex vivo sensitivity to the dual BCL-2/BCL-XL inhibitor navitoclax. In addition, SMAC mimetics were effective in refractory blasts, which correlated with high TNF gene expression in these cells. Ex vivo treatment with the combination of navitoclax and SMAC mimetics further enhanced the eradication of VEN–HMA refractory blasts, although toxicity was also observed in healthy CD34⁺ cells. In conclusion, our integrative analysis identifies molecular signatures associated with primary VEN–HMA resistance and highlights BCL-2/BCL-XL inhibition and SMAC mimetics as therapeutic strategies to target resistance.

Administration of memantine, an antagonist of the N-methyl-d-aspartate receptor, prevents Ca²⁺ overload and dehydration of red blood cells (RBCs) in patients with sickle cell disease (SCD). The objectives of the 1-year dose-escalation Phase IIa/IIb Memantine trial (MeMAGEN – NCT 03247218) with 17 SCD patients who were under stable hydroxycarbamide therapy were to test the drug's safety and tolerability. Daily memantine doses ranged from 5 to 15 mg for children/adolescents and from 5 to 20 mg for adults. Clinical and laboratory analysis showed that memantine was well tolerated. In children, a decrease in days spent in the hospital was observed. Safety was confirmed by laboratory tests, which were not, or were only minimally, altered during memantine therapy. In a subgroup of six patients whose RBCs presented with elevated K⁺ leakage before treatment, memantine therapy at its lowest dosage reduced this K⁺ loss and increased hemoglobin concentration. This study shows that memantine is safe and well tolerated by SCD patients, including children. Memantine has the potential to become a supportive and low-cost therapy in conjunction with hydroxycarbamide.

Chronic red blood cell (RBC) transfusion sustains patients with diverse hematologic disorders, but repeated transfusion leads to iron overload and alloimmunization. Reducing transfusion burden requires identifying donor units that circulate more effectively after storage, yet determinants of this variability remain incompletely defined. Here, we integrate forward genetics in mice, multi-omics analyses of over 13,000 human donors, and studies of two families with hereditary ATP11c mutations to reveal a central role for this phospholipid flippase in transfusion efficacy. We show that common ATP11C variants, including the missense SNP V972M, and rare familial loss-of-function alleles impair RBC survival by disrupting membrane lipid remodeling and cytoskeletal stability—a mechanism distinct from oxidative damage pathways. Together, these findings establish ATP11c as a novel determinant of transfusion outcomes across species and genetic contexts, and highlight opportunities for donor stratification and improved storage technologies to advance precision transfusion medicine.