造血干细胞移植（HSCT）被认为是治愈高危急性白血病（ALL）儿童的方法，能提供更好的生存机会。短串联重复序列已被用作HSCT后嵌合状态的标志物。异基因干细胞移植后出现受体细胞>1%的被定义为混合嵌合状态（MC）。HSCT后的嵌合研究具有动态性。该研究旨在研究HSCT后儿科ALL患者中受体细胞作为原发病复发的预测因子的重要性。MC的发生率为51.4%（37名受者中的19名）。在Day+100期间，MC发生率为48.6%（n = 18），在Day+100后的两年内随访期间，MC发生率为12.9%（31名受者中的4名）。没有发现MC与全身急性移植物抗宿主病的所有级别相关联。全部受者中有35.1%（n = 13）的病死率，中位随访时间为56.9个月（95% CI：39.7-74.2），除了4例（16.7%）处于缓解状态的存活者外。就死亡原因而言，移植相关死亡仅记录在13例死亡患者中的2例（15.4%）；均死于败血症。MC和主要死因之间未发现显著相关性。五年总生存率和无事件生存率的累积概率在MC（≤1.0% vs. > 1.0%）上没有统计学上显着的差异。总之，我们的数据显示MC单独检测不是检测复发的有效预测标记物；对于HSCT后的ALL儿童，应考虑进行分子和流式细胞术分析以监测复发情况。

Hematopoietic stem cell transplantation (HSCT) has been considered curative for children with high-risk acute leukemia (ALL), offering better survival. Short tandem repeat has been used as a marker of chimerism status after HSCT. The appearance of recipient cells >1% post-allogeneic stem cell transplant is defined as mixed chimerism (MC). Chimeric studies post-HSCT are dynamic. This study aimed to investigate the significance of recipient cells in post-HSCT pediatric ALL patients as a predictor of relapse of their primary disease. The rate of MC was 51.4% (19 out of 37 recipients). It was 48.6% (n = 18) during Day+100 and 12.9% (4 out of 31 recipients) during post-Day+100 follow-up until two years. No significant association was noted between MC and all grade overall acute graft-versus-host disease. A mortality rate of 35.1% (n = 13) and a median follow-up of 56.9 months (95% CI: 39.7-74.2) were observed for all but four (16.7%) of the survivors in remission. Regarding causes of death, transplant-related mortality was recorded in only 2 of 13 expired patients (15.4%); both succumbed to sepsis. No significant association was found between MC and primary causes of death. The cumulative probability of five-year overall survival and event-free survival was not found to be statistically significantly different for MC (≤1.0% vs. > 1.0%). In conclusion, our data did not show MC testing alone as an effective prognostic marker for detecting relapse; molecular and flow cytometric analyses should be considered in children with ALL post-HSCT for monitoring relapse.