Application of Gene Expression Microarray for the Classification of Ph-Like B-Cell Acute Lymphoblastic Leukemia.

INTRODUCTION: Ph-like ALL has gene expression profile similar to Ph-positive ALL but without the BCR::ABL1 fusion. The disease presents higher rates of severe clinical features and is associated with unfavorable outcomes. There is still no standard pipeline for molecular characterization of the disease, and no valid predictor gene panel is available worldwide. METHODS: We performed expression microarray on 25 B-cell ALL and 6 Ph-positive B-cell ALL to cluster and identify the transcriptional signature of Ph-like ALL. qRT-PCR was used to confirm the expression of candidate genes. RESULTS: Four out of 25 samples (16%) shared gene expression signatures related to and clustered with control Ph-positive samples. Analysis of genes differentially expressed in Ph-like B-cell ALL and evidentially functional in normal blood cell development and leukemogenesis, we selected genes as potential biomarkers for Ph-like B-cell ALL in our dataset: ADGRE2, CD9, EPHA7, FAM129C, TCL1A, and VPREB1. Those genes were filtered by Ph-like gene signatures obtained from distinct reliable data, resulting in five genes, CA6, CHN2, JAK1, JCHAIN, and PON2, selected for validation by qRT-PCR. The Ct values of genes, including CA6 (p = 0.0017), PON2 (p = 0.0210), TCL1A (p = 0.0064), and VPREB1 (p = 0.0338), were significant in Ph-like ALL. GSEA analysis identified VPREB1 as enrichment in the KRAS signaling pathway, and several genes that interact with VPREB1 were reported as critical molecules involved in the leukemogenesis of B-cell ALL. CONCLUSION: In summary, we demonstrate using a gene expression microarray for classifying Ph-like B-cell ALL and highlight VPREB1 as a potential biomarker for this disease.

[Progress in therapy with L-asparaginase].

L-asparaginase is a key drug in the treatment of acute lymphocytic leukemia/lymphoblastic lymphoma and is currently used in treatment regimens for a wide range of age groups, including children, adolescents, young adults, and older adults. Discontinuation of L-asparaginase leads to worse survival outcomes. Strategies such as appropriate prevention and management of asparaginase-specific adverse events such as hypersensitivity reactions and optimizing administration by therapeutic drug monitoring are important to ensure completion of all asparaginase doses planned in each regimen. Two new L-asparaginase preparations with different properties are now available in Japan, and attempts to leverage these properties for more effective and safe administration are attracting attention. This article reviews previous advances in therapy with L-asparaginase and outlines current and future challenges for maximizing the therapeutic efficacy of L-asparaginase.

The Road More or Less Traveled- Examining the Role of Consolidative Allogeneic Hematopoietic Stem Cell Transplantation After Chimeric Antigen Receptor T Cell Therapy in B-cell ALL.

Treatment with CD19-targeted chimeric antigen receptor T cell therapy (CD19-CART) has improved salvage rates in children and adults with relapsed and/or refractory B-cell acute lymphoblastic leukemia (ALL). However, not all patients treated with CD19-CAR T cells achieve long-term remission. The role of allogeneic hematopoietic stem cell transplantation as consolidative therapy remains undefined. We aim to review the current literature published to date regarding prognostic markers indicating durable ALL response to CD19-CART and risk factors for relapse after CD19-CART to identify patient cohorts who may benefit from consolidative hematopoietic stem cell transplantation.

The impact of Trifolium pratense extract on apoptosis and autophagy in NALM-6 cells: implications for B-ALL intervention.

B-cell acute lymphoblastic leukemia (B-ALL), a prevalent malignancy predominantly affecting children, poses challenges such as drug resistance and cytotoxicity despite available treatment methods. The persistence of these challenges underscores the necessity for innovative therapeutic approaches to enhance efficacy. Natural compounds derived from plants, recognized for their potential to inhibit cancer cell growth, have drawn attention. Trifolium pratense extract, known for its significant anticancer properties in previous studies, was the focus of this investigation. This experimental study aimed to explore the impact of T. pratense extract on apoptosis and autophagy in NALM-6 cells. The cells were exposed to varying concentrations of the extract at specific time intervals, with viability and metabolic activity assessed using Trypan blue exclusion and MTT assays. Flow cytometry was employed to evaluate apoptosis using Annexin V/PI staining and ROS production using DCFH-DA staining. Real-time PCR was used to quantify gene expression related to apoptosis, autophagy, and oxidative stress, with data analysis performed using GraphPad PRISM software. Trifolium pratense extract demonstrated the capacity to induce apoptosis, autophagy, and significantly increase ROS production in NALM-6 cells. These effects were facilitated by the upregulation of corresponding genes. The MTT assay revealed an IC50 of 231 µg/mL at 48 h, and Flow cytometry analysis showed a 51.8% increase in apoptosis in this cell line. Overall, this study emphasizes the effectiveness of T. pratense extract in inducing autophagy and apoptosis pathways in NALM-6 cells derived from B-cell acute lymphoblastic leukemia, suggesting its potential as a candidate for further investigation as a supplement in ALL treatment.

PML mutation and familial pediatric acute lymphoblastic leukemia: A case report.

Hereditary factors contribute to the pathogenesis of pediatric leukemia. However, few studies have reported gene mutation pathopoeias. This paper reports genetic mutations associated with hereditary acute lymphoblastic leukemia. We reported a case of siblings diagnosed with acute lymphoblastic leukemia when aged 3 and 7 years, both siblings are alive after chemotherapy, and whole exome sequencing analysis was performed on the siblings and their parents. It was observed that both siblings had diheterozygous mutations in PML gene (PML, NM_033250, exon7, c.2170A>G, p.S724G; PML, NM_033250, exon7, c.2195G>T, p.G732V), and their parents had heterozygous mutations in one mutation site of PML gene, respectively, suggesting that the diheterozygous mutations of PML gene might be causal genetic genes for the occurrence of acute lymphoblastic leukemia.

Distinct FLT3 Pathways Gene Expression Profiles in Pediatric De Novo Acute Lymphoblastic and Myeloid Leukemia with FLT3 Mutations: Implications for Targeted Therapy.

Activating FLT3 mutations plays a crucial role in leukemogenesis, but identifying the optimal candidates for FLT3 inhibitor therapy remains controversial. This study aims to explore the impacts of FLT3 mutations in pediatric acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) and to compare the mutation profiles between the two types to inspire the targeted application of FLT3 inhibitors. We retrospectively analyzed 243 ALL and 62 AML cases, grouping them into FLT3-mutant and wild-type categories, respectively. We then assessed the associations between FLT3 mutations and the clinical manifestations, genetic characteristics, and prognosis in ALL and AML. Additionally, we compared the distinct features of FLT3 mutations between ALL and AML. In ALL patients, those with FLT3 mutations predominantly exhibited hyperdiploidy (48.6% vs. 14.9%, p < 0.001) and higher FLT3 expression (108.02 [85.11, 142.06] FPKM vs. 23.11 [9.16, 59.14] FPKM, p < 0.001), but lower expression of signaling pathway-related genes such as HRAS, PIK3R3, BAD, MAP2K2, MAPK3, and STAT5A compared to FLT3 wild-type patients. There was no significant difference in prognosis between the two groups. In contrast, AML patients with FLT3 mutations were primarily associated with leucocytosis (82.90 [47.05, 189.76] G/L vs. 20.36 [8.90, 55.39] G/L, p = 0.001), NUP98 rearrangements (30% vs. 4.8%, p = 0.018), elevated FLT3 expression (74.77 [54.31, 109.46] FPKM vs. 34.56 [20.98, 48.28] FPKM, p < 0.001), and upregulated signaling pathway genes including PIK3CB, AKT1, MTOR, BRAF, and MAPK1 relative to FLT3 wild-type, correlating with poor prognosis. Notably, internal tandem duplications were the predominant type of FLT3 mutation in AML (66.7%) with higher inserted base counts, whereas they were almost absent in ALL (6.3%, p < 0.001). In summary, our study demonstrated that the forms and impacts of FLT3 mutations in ALL differed significantly from those in AML. The gene expression profiles of FLT3-related pathways may provide a rationale for using FLT3 inhibitors in AML rather than ALL when FLT3 mutations are present.

Acute lymphoblastic leukemia with nephrogenic diabetes insipidus as the first symptom: a case report.

BACKGROUND: Acute lymphoblastic leukemia is the most common pediatric malignancy, characterized by fever, anemia, hemorrhage, and symptoms brought on by blasts infiltrating organs. CASE PRESENTATION: This is a case report of a 9-year-old Asian patient with acute lymphoblastic leukemia who presented with polyuria alone as a presenting feature without any other clinical manifestation; primary renal disease or inherited metabolic disease was highly suspected. However, the water deprivation test and water deprivation pressurization test suggested nephrogenic diabetes insipidus, and the renal biopsy displayed diffuse lymphocytic infiltration in the renal interstitium. Bone marrow aspiration was performed immediately, and a comprehensive diagnosis of B-lymphoblastic leukemia was finally made. CONCLUSIONS: Renal infiltration with leukemic blasts mostly remains asymptomatic, but our case suggests that it can present with nephrogenic diabetes insipidus. This case fully demonstrates that the presentation of extramedullary infiltration in acute lymphoblastic leukemia is varied. When the patient has renal diabetes insipidus as the first symptom, the possibility of hematological tumor infiltration should be considered when finding the cause, and timely bone marrow cytology should be performed.

Autologous CD7 CAR-T cells generated without T cell pre-selection in pediatric patients with relapsed/refractory T-ALL: A phase I trial.

Chimeric antigen receptor (CAR)-T cell therapy showed preliminary activity in patients with refractory or relapsed T cell acute lymphoblastic leukemia (r/r T-ALL). However, many obstacles remain, including manufacturing difficulties and risk of infections. This phase I study (NCT04840875) evaluated autologous CD7 CAR-T cells manufactured without pre-selection of healthy T cells in r/r T-ALL. Thirty patients (29 children and one adult) with a median of two lines of prior therapy but without detectable peripheral leukemia were enrolled. Excluding three cases of manufacturing failures, a total of 27 (90%) patients received infusions after products were confirmed free of leukemia contamination, including 16 (59%) meeting planned target doses. Common adverse events within 30 days included grade 3-4 cytopenias (100%), grade 1-2 (70%) and 3-4 (7%, including one dose-limiting toxicity) cytokine release syndrome, grade 1 neurotoxicity (7%), grade 2 infection (4%), and grade 2 graft-versus-host disease (4%). Two patients developed grade 2 infections after day 30. At day 30, 96% responded and 85% achieved complete remission (CR) or CR with incomplete hematologic recovery (CRi). Seventy-four percent underwent transplantation. Twelve-month progression-free survival with and without censoring transplantation was 22% (95% confidence interval 4%-100%) and 57% (41%-81%), respectively. These results support that autologous CD7 CAR-T therapy without T cell pre-selection is feasible in patients with r/r T-ALL.

MRD in Acute Leukemias: Lessons Learned from Acute Promyelocytic Leukemia.

Introduction: Advances in molecular biology, polymerase chain reaction (PCR), and next-generation sequencing (NGS) have transformed the concept of minimal residual disease (MRD) from a philosophical idea into a measurable reality. Current Treatment Paradigms and Lessons Learned from APL: Acute promyelocytic leukemia (APL) leads the way in this transformation, initially using PCR to detect MRD in patients in remission, and more recently, aiming to eliminate it entirely with modern treatment strategies. Along the way, we have gained valuable insights that, when applied to other forms of acute leukemia, hold the potential to significantly improve the outcomes of these challenging diseases. Does the BM Microenvironment Play a Role in MRD?: In this review, we explore the current use of MRD in the management of acute leukemia and delve into the biological processes that contribute to MRD persistence, including its overlap with leukemia stem cells and the role of the bone marrow microenvironment.

Case Report: A successful outcome of nadroparin calcium therapy for cerebral venous sinus thrombosis in a child with acute lymphoblastic leukemia.

Background: The appearance of cerebral venous sinus thrombosis (CVST) in childhood acute lymphocytic leukemia (ALL) is a rare life-threatening disease that can cause significant morbidity, neurological sequelae, and potentially poor outcomes. Case presentation: We present the case of a 13-year-old boy with ALL who developed CVST and intrinsic hemorrhage approximately 30 days after receiving chemotherapy with vincristine, dexamethasone, daunorubicin, and pegylated-asparaginase (PEG-Asp). He complained of a severe headache and then developed a generalized seizure at night. T1- and T2-weighted magnetic resonance imaging (MRI) and cerebral magnetic resonance venography sequences revealed superior sagittal sinus thrombosis and intrinsic hemorrhagic changes in the bilateral frontoparietal lobes. He received nadroparin calcium as the anticoagulant treatment and was switched to Erwinia asparaginase (Erwinia Asp) rather than PEG-Asp. Oxcarbazepine and clonazepam were started with good seizure control. Intrathecal treatment was delayed until 1 month later. Anticoagulation treatment was stopped for 24 h before and 6 h after lumbar puncture. Platelet transfusion was administered to ensure the platelet count remained at >50 × 109/L. Oral acetazolamide (500-1,000 mg, daily) was administered to relieve headache and reduce intracranial pressure. Three months later, brain MRI showed a complete resolution of or significant improvement in the filling defect. Nadroparin calcium was administered for 1 week after switching to Erwinia Asp to prevent clot recurrence. He completed the 6-month chemotherapy and is doing well with no neurological sequelae and no recurrence of bleeding or thrombosis. Conclusions: Nadroparin calcium therapy appears to be safe and effective for pediatric CVST with ALL. The reintroduction of Erwinia Asp should be accompanied by anticoagulant therapy with nadroparin calcium.

Overcoming Antigen Escape and T-Cell Exhaustion in CAR-T Therapy for Leukemia.

Leukemia is a prevalent pediatric cancer with significant challenges, particularly in relapsed or refractory cases. Chimeric antigen receptor T-cell (CAR-T) therapy has emerged as a personalized cancer treatment, modifying patients' T cells to target and destroy resistant cancer cells. This study reviews the current therapeutic options of CAR-T therapy for leukemia, addressing the primary obstacles such as antigen escape and T-cell exhaustion. We explore dual-targeting strategies and their potential to improve treatment outcomes by preventing the loss of target antigens. Additionally, we examine the mechanisms of T-cell exhaustion and strategies to enhance CAR-T persistence and effectiveness. Despite remarkable clinical successes, CAR-T therapy poses risks such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Our findings highlight the need for ongoing research to optimize CAR-T applications, reduce toxicities, and extend this innovative therapy to a broader range of hematologic malignancies. This comprehensive review aims to provide valuable insights for improving leukemia treatment and advancing the field of cancer immunotherapy.

Combination Therapy With Asciminib and Ponatinib as a Bridge to Brexucabtagene Autoleucel and Maintenance in a Patient With Relapsed Refractory Philadelphia Positive B-Cell Acute Lymphoblastic Leukemia.

Tyrosine kinase inhibitors (TKIs) have changed the prognosis of Philadelphia-positive B-cell acute lymphoblastic leukemia (ALL); however, relapsed and refractory disease after multiple TKIs continues to be a clinical challenge. Brexucabtagene autoleucel (brexu-cel) is a novel FDA-approved therapy for relapsed and refractory ALL. Given the lengthy manufacturing time, bridging therapy is commonly employed prior to brexu-cel. Here we describe a case of a 75-year-old Hispanic male patient with relapsed/refractory Philadelphia-positive B-cell ALL with extramedullary disease involving abdominal lymph nodes and skin. He was initially treated with chemotherapy in combination with imatinib, and later received dasatinib and subsequently blinatumomab and nilotinib. As the patient progressed, he received ponatinib with low-dose salvage chemotherapy and did not show kinase domain mutation. In a final effort, a novel combination of ponatinib with asciminib was used as a bridge therapy before brexu-cel and later as maintenance therapy after brexu-cel. This novel combination was able to control disease prior to brexu-cel for 2 months and maintained remission for at least 10 months. This report shows that the novel combination of ponatinib and asciminib is tolerable and effective as a bridge and maintenance therapy after brexu-cel.

Acute lymphoblastic leukemia with pneumatosis cystoides intestinalis after hematopoietic stem cell transplantation: a case report.

Pneumatosis cystoides intestinalis (PCI) is a rare condition characterized by air accumulation within the subserosa or submucosa of the gastrointestinal wall. We herein report a case involving a woman in her early 30s who developed PCI after undergoing allogeneic hematopoietic stem cell transplantation (HSCT) for acute lymphoblastic leukemia. The patient had a history of multiple COVID-19 infections. Imaging revealed extensive pneumoperitoneum and mesenteric emphysema; nevertheless, the patient remained clinically stable with a benign abdominal examination. She eventually recovered after 1 month of conservative treatment. We believe the PCI in this case had a multifactorial etiology, potentially involving both HSCT and COVID-19. Raising awareness of PCI may help avoid unnecessary surgical interventions and associated morbidity.

Molecular insights into the hedgehog signaling pathway correlated non-coding RNAs in acute lymphoblastic leukemia, a bioinformatics study.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is a common hematologic cancer with unique incidence and prognosis patterns in people of all ages. Recent molecular biology advances have illuminated ALL's complex molecular pathways, notably the Hedgehog (Hh) signaling system and non-coding RNAs (ncRNAs). This work aimed to unravel the molecular complexities of the link between Hh signaling and ALL by concentrating on long non-coding RNAs (lncRNAs) and their interactions with significant Hh pathway genes. METHODS: To analyze differentially expressed lncRNAs and genes in ALL, microarray data from the Gene Expression Omnibus (GEO) was reanalyzed using a systems biology approach. Hh signaling pathway-related genes were identified and their relationship with differentially expressed long non-coding RNAs (DElncRNAs) was analyzed using Pearson's correlation analysis. A regulatory network was built by identifying miRNAs that target Hh signaling pathway-related mRNAs. RESULTS: 193 DEGs and 226 DElncRNAs were found between ALL and normal bone marrow samples. Notably, DEGs associated with the Hh signaling pathway were correlated to 26 DElncRNAs. Later studies showed interesting links between DElncRNAs and biological processes and pathways, including drug resistance, immune system control, and carcinogenic characteristics. DEGs associated with the Hh signaling pathway have miRNAs in common with miRNAs already known to be involved in ALL, including miR-155-5p, and miR-211, highlighting the complexity of the regulatory landscape in this disease. CONCLUSION: The complex connections between Hh signaling, lncRNAs, and miRNAs in ALL have been unveiled in this study, indicating that DElncRNAs linked to Hh signaling pathway genes could potentially serve as therapeutic targets and diagnostic biomarkers for ALL.

Single-cell multi-omics reveal stage of differentiation and trajectory-dependent immunity-related gene expression patterns in human erythroid cells.

The role of Erythroid cells in immune regulation and immunosuppression is one of the emerging topics in modern immunology that still requires further clarification as Erythroid cells from different tissues and different species express different immunoregulatory molecules. In this study, we performed a thorough investigation of human bone marrow Erythroid cells from adult healthy donors and adult acute lymphoblastic leukemia patients using the state-of-the-art single-cell targeted proteomics and transcriptomics via BD Rhapsody and cancer-related gene copy number variation analysis via NanoString Sprint Profiler. We found that human bone marrow Erythroid cells express the ARG1, LGALS1, LGALS3, LGALS9, and C10orf54 (VISTA) immunosuppressive genes, CXCL5, CXCL8, and VEGFA cytokine genes, as well as the genes involved in antimicrobial immunity and MHC Class II antigen presentation. We also found that ARG1 gene expression was restricted to the single erythroid cell cluster that we termed ARG1-positive Orthochromatic erythroblasts and that late Erythroid cells lose S100A9 and gain MZB1 gene expression in case of acute lymphoblastic leukemia. These findings show that steady-state erythropoiesis bone marrow Erythroid cells express myeloid signature genes even without any transdifferentiating stimulus like cancer.

Preliminary exploration of the expression of acetylcholinesterase in normal human T lymphocytes and leukemic Jurkat T cells.

The classic enzymatic function of acetylcholinesterase (AChE) is the hydrolysis of acetylcholine (ACh) in the neuronal synapse. However, AChE is also present in nonneuronal cells such as lymphocytes. Various studies have proposed the participation of AChE in the development of cancer. The ACHE gene produces three mRNAs (T, H and R). AChE-T encodes amphiphilic monomers, dimers, tetramers (G1 A, G2 A and G4 A) and hydrophilic tetramers (G4 H). AChE-H encodes amphiphilic monomers and dimers (G1 A and G2 A). AChE-R encodes a hydrophilic monomer (G1 H). The present study considered the differences in the mRNA expression (T, H and R) and protein levels of AChE, as well as the molecular forms of AChE, the glycosylation pattern and the enzymatic activity of AChE present in normal T lymphocytes and leukemic Jurkat E6-1 cells. The results revealed that AChE enzymatic activity was higher in normal T lymphocytes than in Jurkat cells. Normal T cells expressed AChE-H transcripts, whereas Jurkat cells expressed AChE-H and AChE-T. The molecular forms identified in normal T cells were G2 A (5.2 S) and G1 A (3.5 S), whereas those in Jurkat cells were G2 A (5.2 S), G1 A (3.5 S) and G4 H (10.6S). AChE in Jurkat cells showed altered posttranslational maturation since a decrease in the incorporation of galactose and sialic acid into its structure was observed. In conclusion, the content and composition of AChE were altered in Jurkat cells compared with those in normal T lymphocytes. The present study opened new avenues for exploring the development of novel therapeutic strategies against T-cell leukemia and for identifying potential molecular targets for the early detection of this type of cancer.

Integrative alternative splicing analysis reveals new prognosis signature in B-cell acute lymphoblastic leukemia.

The dysregulation of alternative splicing (AS) is increasingly recognized as a pivotal player in the pathogenesis, progression, and treatment resistance of B-cell acute lymphoblastic leukemia (B-ALL). Despite its significance, the clinical implications of AS events in B-ALL remain largely unexplored. This study developed a prognostic model based on 18 AS events (18-AS), derived from a meticulous integration of bioinformatics methodologies and advanced machine learning algorithms. The 18-AS signature observed in B-ALL distinctly categorized patients into different groups with significant differences in immune infiltration, V(D)J rearrangement, drug sensitivity, and immunotherapy outcomes. Patients classified within the high 18-AS group exhibited lower immune infiltration scores, poorer chemo- and immune-therapy responses, and worse overall survival, underscoring the model's potential in refining therapeutic strategies. To validate the clinical applicability of the 18-AS, we established an SF-AS regulatory network and identified candidate drugs. More importantly, we conducted in vitro cell proliferation assays to confirm our analysis, demonstrating that the High-18AS cell line (SUP-B15) exhibited significantly enhanced sensitivity to Dasatinib, Dovitinib, and Midostaurin compared to the Low-18AS cell line (REH). These findings reveal AS events as novel prognostic biomarkers and therapeutic targets, advancing personalized treatment strategies in B-ALL management.

The significance of CD49f expression in pediatric B-cell acute lymphoblastic leukemia.

OBJECTIVES: CD49f is an adhesion molecule present on malignant lymphoblasts in B-cell acute lymphoblastic leukemia; it is associated with a poor prognosis. CD49f expression has been proposed as a marker for measurable residual disease (MRD) marker, but this marker has yet to be implemented in clinical practice. METHODS: In this study, we used flow cytometry to detect CD49f expression by leukemic blasts in paired bone marrow and cerebrospinal fluid samples at diagnosis and bone marrow at day 15 of treatment. RESULTS: At diagnosis, 93% of bone marrow and 100% of cerebrospinal fluid lymphoblasts expressed CD49f. The intensity of CD49f expression statistically significantly increased during treatment (P < .001). In MRD-negative end-of-treatment samples, only a small population of hematogones expressed CD49f. Interestingly, the intensity of CD49f expression varied among the different groups of recurrent genetic abnormalities. The ETV6::RUNX1 fusion and ETV6::RUNX1 combined with the high hyperdiploid group were associated with increased expression, whereas the Philadelphia-like group showed low CD49f expression. The lower CD49f expression at diagnosis predicted a lower MRD rate at day 15 of treatment. CONCLUSIONS: We concluded that CD49f can be used as an MRD marker and possible prognostic factor in B-cell acute lymphoblastic leukemia.

Human leukocyte antigen evolutionary divergence as a novel risk factor for donor selection in acute lymphoblastic leukemia patients undergoing haploidentical hematopoietic stem cell transplantation.

Introduction: The human leukocyte antigen (HLA) evolutionary divergence (HED) reflects immunopeptidome diversity and has been shown to predict the response of tumors to immunotherapy. Its impact on allogeneic hematopoietic stem cell transplantation (HSCT) is controversial in different studies. Methods: In this study, we retrospectively analyzed the clinical impact of class I and II HED in 225 acute lymphoblastic leukemia patients undergoing HSCT from related haploidentical donors. The HED for recipient, donor, and donor-recipient pair was calculated based on Grantham distance, which accounts for variations in the composition, polarity, and volume of each amino acid within the peptide-binding groove of two HLA alleles. The median value of HED scores was used as a cut-off to stratify patients with high or low HED. Results: The class I HED for recipient (R_HEDclass I) showed the strongest association with cumulative incidence of relapse (12.2 vs. 25.0%, P = 0.00814) but not with acute graft-versus-host disease. The patients with high class II HED for donor-recipient (D/R_HEDclass II) showed a significantly higher cumulative incidence of severe aGVHD than those with low D/R_HEDclass II (24.0% vs. 6.1%, P = 0.0027). Multivariate analysis indicated that a high D/R_HEDclass II was an independent risk factor for the development of severe aGVHD (P = 0.007), and a high R_HEDclass I had a more than two-fold reduced risk of relapse (P = 0.028). However, there was no discernible difference in overall survival (OS) or disease-free survival (DFS) for patients with high or low HED, which was inconsistent with the previous investigation. Discussion: While the observation are limited by the presented single center retrospective cohort, the results show that HED has poor prognostic value in OS or DFS, as well as the associations with relapse and aGVHD. In haploidentical setting, class II HED for donor-recipient pair (D/R_HEDclass II) is an independent and novel risk factor for finding the best haploidentical donor, which could potentially influence clinical practice if verified in larger cohorts.

Backtracking childhood leukaemia to birth: A battle of addition.

Paediatric leukaemia has a long tail of driver mutations each of which must be 'backtracked' to samples taken at birth to identify the prenatal origin of a subtype. Presently, Bardini et al. describe the first successful backtracking of an NUTM1 rearrangement, which sheds light on the biology of this particular alteration. Continued backtracking of NUTM1 rearrangements, and all leukaemia-typical somatic alterations, is necessary to fully understand the prenatal origin of these diseases. Commentary on: Bardini et al. Prenatal origin of NUTM1 gene rearrangement in infant B-cell precursor acute lymphoblastic leukaemia. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19685.