Genetic and clinical characteristics of acute B-cell lymphoblastic leukemia with MEF2D fusions and report of two novel MEF2D rearrangements.

The MEF2D rearrangement is a recurrent chromosomal abnormality detected in approximately 2.4-5.3% of patients with acute B-cell lymphoblastic leukemia (B-ALL). Currently, MEF2D-rearranged B-ALL is not classified as an independent subtype in the WHO classification. Consequently, the clinical significance of MEF2D rearrangement in B-ALL remains largely unexplored. In this study, we retrospectively screened 260 B-ALL patients with RNA sequencing data collected between November 2018 and December 2022. Among these, 10 patients were identified with MEF2D rearrangements (4 with MEF2D::HNRNPUL1, 3 with MEF2D::BCL9, 1 with MEF2D::ARID1B, 1 with MEF2D::DAZAP1 and 1 with MEF2D::HNRNPM). Notably, HNRNPM and ARID1B are reported as MEF2D fusion partners for the first time. The patient with the MEF2D::HNRNPM fusion was resistant to chemotherapy and chimeric antigen receptor T-cell therapy and relapsed early after allogenic stem cell transplantation. The patient with MEF2D::ARID1B experienced early extramedullary relapse after diagnosis. All 10 patients achieved complete remission after induction chemotherapy. However, 9/10 (90%) of whom experienced relapse. Three of the 9 patients relapsed with aberrant expression of myeloid antigens. The median overall survival of these patients was only 11 months. This small cohort showed a high incidence of early relapse and short survival in patients with MEF2D rearrangements.

Targeted therapy and immunotherapy for T cell acute lymphoblastic leukemia/lymphoma.

T cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) is an aggressive malignancy of progenitor T cells. Despite significant improvements in survival of T-ALL/LBL over the past decades, treatment of relapsed and refractory T-ALL (R/R T-ALL/LBL) remains extremely challenging. The prognosis of R/R T-ALL/LBL patients who are intolerant to intensive chemotherapy remains poor. Therefore, innovative approaches are needed to further improve the survival of R/R T-ALL/LBL patients. With the widespread use of next-generation sequencing in T-ALL/LBL, a range of new therapeutic targets such as NOTCH1 inhibitors, JAK-STAT inhibitors, and tyrosine kinase inhibitors have been identified. These findings led to pre-clinical studies and clinical trials of molecular targeted therapy in T-ALL/LBL. Furthermore, immunotherapies such as CD7 CAR T cell therapy and CD5 CAR T cell therapy have shown profound response rate in R/R T-ALL/LBL. Here, we review the progress of targeted therapies and immunotherapies for T-ALL/LBL, and look at the future directions and challenges for the further use of these therapies in T-ALL/LBL.

Weathering the storm: diagnosis and treatment of a life-threatening disseminated Nocardia otitidiscaviarum infection.

Nocardiosis demonstrates a temporal categorization that includes acute, subacute, and chronic stages alongside distinct typical localizations such as pulmonary, cutaneous, and disseminated forms. Disseminated nocardiosis, commonly caused by Nocardia asteroides, N. brasiliensis, and N. farcinica, continues to result in substantial morbidity and mortality. Herein, we report a life-threatening disseminated nocardiosis caused by Nocardia otitidiscaviarum in a patient with minimal change disease. This study emphasizes the difficulty in the diagnosis and treatment of unknown infections in clinical settings and highlights the important role played by laboratories in solving infectious diseases caused by rare pathogens.

Investigations of the prognostic value of RUNX1 mutation in acute myeloid leukemia patients: Data from a real-world study.

RUNX1 is one of the recurrent mutated genes in newly diagnosed acute myeloid leukemia (AML). Although historically recognized as a provisional distinct entity, the AML subtype with RUNX1 mutations (AML-RUNX1mut) was eliminated from the 2022 WHO classification system. To gain more insight into the characteristics of AML-RUNX1mut, we retrospectively analyzed 1065 newly diagnosed adult AML patients from the First Affiliated Hospital of Soochow University between January 2017 and December 2021. RUNX1 mutations were identified in 112 patients (10.5%). The presence of RUNX1 mutation (RUNX1mut) conferred a lower composite complete remission (CRc) rate (40.2% vs. 58.4%, P＜0.001), but no significant difference was observed in the 5-year overall survival (OS) rate (50.2% vs. 53.9%; HR=1.293; P=0.115) and event-free survival (EFS) rate (51.5% vs. 49.4%; HR=1.487, P=0.089), even within the same risk stratification. Multivariate analysis showed that RUNX1mut was not an independent prognostic factor for OS (HR=1.352, P=0.068) or EFS (HR=1.129, P=0.513). When patients were stratified according to induction regimen, RUNX1mut was an unfavorable factor for CRc both on univariate and multivariate analysis in patients receiving conventional chemotherapy, and higher risk stratification predicted worse OS. In those who received venetoclax plus hypomethylating agents, RUNX1mut was not predictive of CRc and comparable OS and EFS were seen between intermediate-risk and adverse-risk groups. The results of this study revealed that the impact of RUNX1mut is limited. Its prognostic value depended more on treatment and co-occurrent abnormalities. VEN-HMA may abrogate the prognostic impact of RUNX1, which merits a larger prospective cohort to illustrate.

Classification and prediction of Klebsiella pneumoniae strains with different MLST allelic profiles via SERS spectral analysis.

The Gram-negative non-motile Klebsiella pneuomoniae is currently a major cause of hospital-acquired (HA) and community-acquired (CA) infections, leading to great public health concern globally, while rapid identification and accurate tracing of the pathogenic bacterium is essential in facilitating monitoring and controlling of K. pneumoniae outbreak and dissemination. Multi-locus sequence typing (MLST) is a commonly used typing approach with low cost that is able to distinguish bacterial isolates based on the allelic profiles of several housekeeping genes, despite low resolution and labor intensity of the method. Core-genome MLST scheme (cgMLST) is recently proposed to sub-type and monitor outbreaks of bacterial strains with high resolution and reliability, which uses hundreds or thousands of genes conserved in all or most members of the species. However, the method is complex and requires whole genome sequencing of bacterial strains with high costs. Therefore, it is urgently needed to develop novel methods with high resolution and low cost for bacterial typing. Surface enhanced Raman spectroscopy (SERS) is a rapid, sensitive and cheap method for bacterial identification. Previous studies confirmed that classification and prediction of bacterial strains via SERS spectral analysis correlated well with MLST typing results. However, there is currently no similar comparative analysis in K. pneumoniae strains. In this pilot study, 16 K. pneumoniae strains with different sequencing typings (STs) were selected and a phylogenetic tree was constructed based on core genome analysis. SERS spectra (N = 45/each strain) were generated for all the K. pneumoniae strains, which were then comparatively classified and predicted via six representative machine learning (ML) algorithms. According to the results, SERS technique coupled with the ML algorithm support vector machine (SVM) could achieve the highest accuracy (5-Fold Cross Validation = 100%) in terms of differentiating and predicting all the K. pneumoniae strains that were consistent to corresponding MLSTs. In sum, we show in this pilot study that the SERS-SVM based method is able to accurately predict K. pneumoniae MLST types, which has the application potential in clinical settings for tracing dissemination and controlling outbreak of K. pneumoniae in hospitals and communities with low costs and high rapidity.