异基因造血干细胞移植（allo-HSCT）后的免疫重建对于预防感染和复发以及增强移植物抗肿瘤作用至关重要。 B细胞在体液免疫和免疫调节中发挥着重要作用，但其在allo-HSCT后的重建尚未得到很好的研究。在本研究中，我们分析了252例接受allo-HSCT 2年的患者的B细胞动态，并评估影响B细胞重建的因素及其与生存结果的相关性，以及骨髓中B细胞和外周血亚群的发育阶段。我们发现骨髓中B细胞重建与外周血一致（p = 0.232）。 B细胞重建因男性、年龄>50、供体年龄较大、慢性和急性移植物抗宿主病的发生以及真菌和巨细胞病毒的感染而延迟。生存分析显示，B 细胞水平较低的患者死亡和复发的风险较高。更重要的是，我们使用倾向评分匹配得出了女性 1 年后 B 细胞重建更好的结论。同时，通过中介分析，我们提出了年龄-B 细胞-存活轴，并发现移植后第 12 个月的 B 细胞重建介导了年龄对患者存活的影响 (p = 0.013)。我们还发现，年轻患者在移植后骨髓中显示出更多未成熟的 B 细胞 (p = 0.037)。我们的研究结果为优化 B 细胞重建管理和提高 allo-HSCT 的疗效和安全性提供了宝贵的见解。© 2024作者们。约翰·威利出版的《内科杂志》

The immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is crucial for preventing infections and relapse and enhancing graft-versus-tumor effects. B cells play an important role in humoral immunity and immune regulation, but their reconstitution after allo-HSCT has not been well studied.In this study, we analyzed the dynamics of B cells in 252 patients who underwent allo-HSCT for 2 years and assessed the impact of factors on B-cell reconstitution and their correlations with survival outcomes, as well as the development stages of B cells in the bone marrow and the subsets in the peripheral blood.We found that the B-cell reconstitution in the bone marrow was consistent with the peripheral blood (p = 0.232). B-cell reconstitution was delayed by the male gender, age >50, older donor age, the occurrence of chronic and acute graft-versus-host disease, and the infections of fungi and cytomegalovirus. The survival analysis revealed that patients with lower B cells had higher risks of death and relapse. More importantly, we used propensity score matching to obtain the conclusion that post-1-year B-cell reconstitution is better in females. Meanwhile, using mediation analysis, we proposed the age-B cells-survival axis and found that B-cell reconstitution at month 12 posttransplant mediated the effect of age on patient survival (p = 0.013). We also found that younger patients showed more immature B cells in the bone marrow after transplantation (p = 0.037).Our findings provide valuable insights for optimizing the management of B-cell reconstitution and improving the efficacy and safety of allo-HSCT.© 2024 The Authors. Journal of Internal Medicine published by John Wiley & Sons Ltd on behalf of Association for Publication of The Journal of Internal Medicine.