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The number of umbilical cord blood transplantation (U-CBT) procedures has been growing annually, but little research has been done on long-term immune recovery after U-CBT. Infection risk is high in U-CBT recipients, and this can be partially attributed to immature immunocompetent cells in umbilical cord blood. In this study, we analyzed lymphocyte subset (LST) number to determine the long-term recovery timeline. We included 36 U-CBT and 10 unrelated bone marrow transplantation (U-BMT) recipients who survived more than 2 years after transplantation, and followed them for up to 10 years post-transplant. Recovery kinetics in the early phase post-transplant was different for each LST. Recovery of CD19 + B cells was faster after U-CBT than after U-BMT in the first 5 years after transplantation. Although CD4 + T cells increased in the first several months after U-CBT, long-term cell count recovery was impaired in approximately 20% of patients. Thus, although the LST recovery pattern after U-CBT was unique, LST number recovery was statistically comparable between U-CBT and U-BMT past 5 years post-transplantation., (© 2024. Japanese Society of Hematology.)

Acquired point mutations in the ABL1 gene are widely recognized as a cause of Philadelphia chromosome-positive B cell precursor acute lymphoblastic leukemia (Ph + B-ALL) that is resistant to tyrosine kinase inhibitors, whereas there are few reports about other types of the ABL1 mutation. Here, we report 2 cases of Ph + B-ALL gaining a partial deletion type mutation of the ABL1 gene (Δ184-274 mutation), which resulted in truncation of the ABL1 molecule and loss of kinase activity. In both cases, the disease was refractory to multiple agents in the recurrent phase after allogeneic hematopoietic cell transplantation. This is a case report of a truncated ABL1 mutation in 2 patients with Ph + B-ALL., (© 2024. Japanese Society of Hematology.)

Amyloid light chain (AL) amyloidosis is a rare hematologic disease that may involve multiple organs. Amongst the organs, cardiac involvement causes the greatest concern as its treatment is challenging. Diastolic dysfunction rapidly progresses to decompensated heart failure, pulseless electrical activity, and atrial standstill due to electro-mechanical dissociation resulting in death. High-dose melphalan plus autologous stem cell transplantation (HDM-ASCT) is the most radical treatment but its risk is very high and thus only less than 20% of patients can receive this therapy under criteria that can suppress treatment-related mortality. In substantial proportion of patients, levels of M protein remain elevated, and organ response cannot be achieved. Moreover, relapse may occur, making prediction of treatment response and judgement of disease eradication very difficult. Herein we report a case of AL amyloidosis who was treated with HDM-ASCT, resulting in preserved cardiac function and resolution of proteinuria for more than 17 years after HDM-ASCT ensuing atrial fibrillation and complete atrioventricular block required management by catheter ablation and pacemaker implantation 10 years and 12 years after transplantation, respectively., (© 2023. The Author(s) under exclusive licence to The Japan Society of Nephrology.)

Bacterial meningitis is a rare but severe infectious complication after hematopoietic stem cell transplantation. However, its clinical features were previously not clear. We reviewed the cases of 7 patients diagnosed with bacterial meningitis with a positive cerebrospinal fluid culture among 1147 patients who underwent cord blood transplantation (CBT) at our institution between September 2007 and September 2020. The diagnosis was made on day + 5- + 45, and 5 patients developed bacterial meningitis before neutrophil engraftment. The causative organisms were all Gram-positive cocci: Enterococcus faecium and Enterococcus gallinarum (2 patients each), and Staphylococcus haemolyticus, Streptococcus mitis/oralis, and Rothia mucilaginosa (1 patient each). Six patients developed bacterial meningitis secondary to prior or concomitant bacteremia caused by the same bacterium. Five patients had received anti-MRSA agents at onset: vancomycin in 3, teicoplanin in 1, and daptomycin in 1. After diagnosis of bacterial meningitis, linezolid was eventually used for 6 patients. Two patients with E. gallinarum were alive at day + 1380 and + 157 after CBT, respectively, whereas 5 patients died 17-53 (median 43) days after the onset of bacterial meningitis. Breakthrough meningitis in CBT can occur even during the use of anti-MRSA drugs, and intensive antibiotic treatment is necessary., (© 2022. Japanese Society of Hematology.)

Acute lymphoblastic leukemia (ALL) is a common neoplasm in children, but less frequent in adults. Since information on clinical features and genetics of adult ALL in Japan is limited, we analyzed 215 subjects aged 16-65 years with untreated ALL enrolled in the Fukuoka Blood & Marrow Transplant Group studies ALL MRD 2002 and 2008. The prevalence of ALL was bimodal, with the larger group aged 56-65 years. Immunophenotypic characterization showed B-lineage is more frequent than T-lineage ALL (78.6 vs 13.0%), with age-related differences. The proportion with BCR-ABL1 rearrangement increased progressively with age, up to 55.7% among subjects aged over 56-65 years. Rearrangements involving the KMT2A gene, ETV6-RUNX1, and TCF3-PBX1 were rare in this study cohort. The overall incidence of hyperdiploidy was only 1.7%, and there were no cases with hypodiploidy. Overall survival varied by age and cytogenetics. Older subjects and those with BCR-ABL1 tended to have inferior outcomes. In this epidemiological study of Japanese adult ALL, the majority of subjects had B-lineage ALL, the T-cell phenotype was most frequent in those aged 16-25, and BCR-ABL1 rearrangement was very common, with prevalence increasing with age. These types of adult ALL are potentially manageable with targeted therapies.

We report a 58-year-old Japanese woman who presented with nephrotic syndrome. Steroid therapy and cyclosporine A administration were initiated, but hematological remission and renal response were not achieved. Renal biopsy revealed amyloid deposits in the mesangial region and the small arteries. Proteomic analysis based on laser microdissection and mass spectrometry showed that the amyloid deposits were composed of the constant region of the lambda light chain. She received vincristine, adriamycin, and dexamethasone therapy followed by high-dose melphalan and autologous stem cell transplantation, resulting in hematological complete remission and renal response with negative urinary Bence-Jones protein and proteinuria. Renal biopsy was performed four times during follow-up, demonstrating that amyloid deposits decreased gradually, while glomeruli showing global sclerosis increased from 3 to 62%. This case suggests that glomerular amyloid deposits can be cleared via tissue remodeling, if stem cells producing amyloid precursors are completely replaced by unrelated cells after stem cell transplantation.