Chimerism analysis following hematopoietic stem cell transplantation (HSCT) for leukemia is routinely applied in parallel with quantification of minimal residual disease (MRD) to identify imminent relapse. In the past decades, new methods with a lower limit of detection compared to standard methods have been developed, so-called microchimerism analysis. Microchimerism analysis is fast, simple, applicable across pre-HSCT disease-type and can be applied on peripheral blood allowing frequent testing during follow-up. Monitoring of microchimerism in blood could replace repeated bone marrow analysis for MRD and allow earlier detection of imminent relapse or graft failure. Clinical studies in single center cohorts have shown conflicting but promising results. There is currently no consensus on the interpretation of microchimerism analysis and heterogeneity of studies remains a major obstacle for inter-study comparisons and meta-analysis in this field. We have conducted a systematic review of studies investigating associations between microchimerism and relapse of leukemia post-HSCT. We summarize current evidence and provide suggestions for future research.

白血病的造血干细胞移植（HSCT）后的嵌合分析通常与最小残留疾病（MRD）的定量分析并行进行，以识别即将发生的复发。在过去的几十年中，已经开发出比标准方法具有更低检测限的新方法，即所谓的微嵌合体分析。微嵌合体分析快速，简单，适用于HSCT之前的疾病类型，并且可以应用于外周血，从而可以在随访期间进行频繁的检测。监测血液中的微嵌合体可以代替针对MRD的重复骨髓分析，并可以更早地检测到即将发生的复发或移植失败。在单中心队列研究中，临床研究显示出矛盾但有希望的结果。目前关于微嵌合体分析的解释尚无共识，研究的异质性仍然是该领域研究比较和荟萃分析的主要障碍。我们对研究HSCT后白血病的微嵌合体与白血病复发之间的关系进行了系统的综述。我们总结了目前的证据，并为以后的研究提供了建议。