British Journal of Haematology最新文献

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) is a haemato-inflammatory syndrome genetically defined by somatic mutations in the X-linked UBA1 gene, typically Val/Thr/Leu substitutions at the Met41 hotspot. Clinical manifestations are heterogeneous and refractory to most haemato-rheumatological treatments. To date, no guidelines exist for the management of VEXAS, and scarce is the evidence on methodology and clinical significance of longitudinal UBA1 clonal burden evaluation upon therapy. Here, we validated a method to quantify UBA1 clonal burden and explored its applicability in patients with VEXAS. Given the different treatment interactions, droplet digital polymerase chain reaction (ddPCR) may allow for informed therapeutic decisions and implementation of personalized strategies.

Red blood cell (RBC) antigen matching beyond ABO and RhD is commonly recommended for patients with sickle cell disease (SCD) and thalassaemia. We present an updated systematic literature review to inform evidence-based guidelines on RBC matching. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool was used to develop recommendations. Six new observational studies (4 prospective, 2 retrospective) were identified. The six studies reported on 583 patients in total, including cross-over designs, with sample sizes from 10 to 343. Studies were heterogeneous, utilising varying degrees of RBC matching and different definitions for 'extended' matching. All reported on alloimmunisation. One study reported on molecular matching. The reported prevalence of alloimmunisation using limited matching was 0%-50% and with extended matching was 0%-24%. Eighty-two patients were alloimmunised before study entry. The risk of bias across studies was moderate to critical. The guideline panel recommends that ABO, RhDCcEe, and K-compatible RBCs are selected for individuals with SCD and thalassaemia, even in the absence of alloantibodies, and that RBCs which are antigen-negative to already existing clinically significant antibodies are chosen. There is a need for comparative research to define the benefit, impact, cost-effectiveness, and feasibility of extended RBC matching strategies to prevent alloimmunisation.

Can peripheral blood be used to detect residual disease in acute lymphoblastic leukaemia (ALL) when we increase the sensitivity of the method used? Bendig et al. found that a larger amount of material and the use of next-generation sequencing (NGS) detects MRD in peripheral blood in up to half of patients with B-cell precursor ALL (BCP-ALL) where routine examination was negative. However, a negative result does not exclude the presence of residual disease and thus still limits the use of peripheral blood. Commentary on: Bendig et al. Next-generation sequencing and high DNA input identify previously missed measurable residual disease in peripheral blood of B-cell precursor acute lymphoblastic leukaemia. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19834.

Haematopoietic stem and progenitor cell (HSPC) autologous gene therapies are promising treatment for a variety of blood disorders. Investigation of the long-term HSPC clonal dynamics and other measures of safety and durability following lentiviral-mediated gene therapies in predictive models are crucial for assessing risks and benefits in order to inform decisions regarding wider utilization. We established an autologous lentivirally barcoded HSPC transplantation model in rhesus macaque (RM), a model offering insights into haematopoiesis and gene therapies with direct relevance to human. Healthy young adult RMs underwent total body irradiation, followed by transplantation of autologous HSPCs transduced with a lentiviral vector containing a diverse genetic barcode library, uniquely labelling individual HSPCs and their progeny. With up to 131 months of follow-up, we now report quantitative clonal dynamics, characterizing the number, diversity, stability and lineage bias of hundreds of thousands of HSPC clones tracked in five RMs. We documented long-term stable and multi-lineage output from a highly polyclonal pool of HSPCs. Clonal succession after stable haematopoietic reconstitution was minimal. There was no evidence for accelerated acquisition of acquired somatic mutations following autologous lentivirally transduced HSPC transplantation. Our results provide relevant insights into long-term HSPC behaviours in vivo following transplantation and gene therapies.

Therapeutic approaches for acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS) differ due to distinct diagnostic criteria and treatment strengths. However, reliable biomarkers to differentiate AML from MDS are needed. This study investigated transfer RNA (tRNA) modifications, particularly hydroxy-wybutosine (OHyW), in the transition from MDS to AML. We found a significant decrease in OHyW and its biosynthetic enzyme leucine carboxyl methyltransferase 2 (LCMT2, alias symbol is TYW4) levels in AML compared to MDS. Mass spectrometric analysis revealed distinct tRNA modification patterns, with AML showing decreased OHyW and increased precursor levels, indicating a disrupted biosynthetic pathway. Lower LCMT2 expression correlated with reduced drug sensitivity and limited differentiation potential in AML cell lines. The results highlight the pivotal role of tRNA modifications in the progression from MDS to AML and suggest that targeting LCMT2 may enhance therapeutic outcomes in AML. By understanding these molecular mechanisms, we can develop new diagnostic markers and therapeutic strategies, potentially transforming the clinical management of AML and improving patient outcomes.

In this article, Chen et al. show that a chemical modification of transfer RNA, along its corresponding RNA modifier enzyme, is diminished in acute myeloid leukaemia. These findings further support the role of an aberrant epitranscriptome in haematological malignancies. Commentary on: Chen et al. Hydroxy-wybutosine tRNA modifications as indicators of disease progression and therapeutic targets in leukemia. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19873.

Children diagnosed with acute myeloid leukaemia (paediatric AML [pAML]) have limited treatment options and relapse rates due to chemoresistance and refractory disease are over 30%. Current treatment is cytotoxic and in itself has long-lasting harsh side effects. New, less toxic treatments are needed. The bone marrow microenvironment provides chemoprotection to leukaemic cells through cell communication and interaction with mesenchymal stem cells (MSCs), but this is not well defined in pAML. Using primary patient material, we identify a cell contact-independent mechanism of MSC-mediated chemoprotection involving extrinsic soluble factors that is abrogated through inhibition of the JAK/STAT and ERK pathways.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare prothrombotic disorder with a unique clonality-restricted immunological profile. The study by Petito and Bury et al. provides insight into the role of HLA polymorphisms and an inherent predisposition to VITT. Commentary on: Petito et al. Association of human leucocyte antigen loci with vaccine-induced immune thrombotic thrombocytopenia: Potential role of the interaction between platelet factor 4-derived peptides and MHC-II. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19838.