目的 探讨儿童异基因造血干细胞移植（allo-HSCT）后免疫重建的临床特性。方法 选取2019年7月至2020年10月接受allo-HSCT且临床资料完整的患儿为研究对象。动态监测患儿移植后第0、14、21、28、60及100 d外周血淋巴细胞亚群（CD3⁺ T细胞、CD4⁺ T细胞、CD8⁺ T细胞、CD16⁺ CD56⁺ NK细胞、CD19⁺ B细胞、CD4⁺ CD25⁺ Treg细胞）绝对计数;将患儿按有无急性移植物抗宿主病（aGVHD）分为non-aGVHD组和aGVHD组,比较两组间淋巴细胞亚群的差异。结果 共75例患儿接受allo-HSCT,其中移植后满100 d、临床资料完整的42例患儿纳入本研究,男20例、女22例,中位年龄5.4（2.8~9.3）岁。移植前后不同时间点之间患儿CD3⁺ T细胞、CD4⁺ T细胞、CD8⁺ T细胞、CD16⁺ CD56⁺ NK细胞、CD19⁺ B细胞、CD4⁺CD25⁺ Treg细胞水平以及CD4⁺/CD8⁺比值差异均有统计学意义（P<0.05）。其中CD16⁺ CD56⁺ NK细胞恢复最快,在移植后21 d基本可达到移植前水平;CD3⁺ T细胞在移植后60 d基本可以达到移植前水平,CD8⁺ T 细胞到移植后60 d已超过移植前水平。42例患儿中发生aGVHD 16例,aGVHD 发生的中位时间为20.0（6.0~36.0）d。移植后28 d和60 d,aGVHD 组CD16⁺ CD56⁺ NK细胞绝对计数均低于non-aGVHD 组,差异有统计学意义（P<0.05）。结论 儿童allo-HSCT后淋巴细胞亚群中重建最早的为CD16⁺ CD56⁺ NK细胞。NK细胞重建与aGVHD 的发生密切相关,或有助于早期识别aGVHD 患儿。

Objective To investigate the clinical characteristics of immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children. Methods Children with complete clinical data who received allo-HSCT in the department of hematology and oncology from July 2019 to October 2020 were selected as the study subjects. The absolute count of peripheral blood lymphocyte subsets (CD3⁺ T cells, CD4⁺ T cells, CD8⁺ T cells, CD16⁺ CD56⁺ NK cells, CD19⁺ B cells, CD4⁺ CD25⁺ Treg cells) was dynamically monitored on day 0, 14, 21, 28, 60 and 100 after transplantation. The children were divided into non-aGVHD group and aGVHD group according to the presence or absence of acute graft-versus-host disease (aGVHD), and the differences of lymphocyte subsets between the two groups were compared. Results A total of 75 children received allo-HSCT, and 42 of them with complete clinical data after 100 days of transplantation were included in this study. There were 20 boys and 22 girls with a median age of 5.4 (2.8~9.3) years. There were statistically significant differences in the levels of CD3⁺ T cells, CD4⁺ T cells, CD8⁺ T cells, CD16⁺ CD56⁺ NK cells, CD19⁺B cells, CD4⁺CD25⁺ Treg cells and CD4⁺/CD8⁺ ratio at different time points before and after transplantation (P<0.05). CD16⁺CD56⁺ NK cells recovered the earliest and reached the level of pre-transplantation at 21 days post-transplantation. CD3⁺ T cells almost reached the pre-transplantation level at 60 days after transplantation, while CD8⁺ T cells exceeded the pre-transplantation level at 60 days after transplantation. The aGVHD occurred in 16 of 42 children, and the median time of aGVHD occurrence was 20.0 (6.0-36.0) days. At 28d and 60d after transplantation, the absolute count of CD16⁺ CD56⁺ NK cells in aGVHD group was lower than that in non-aGVHD group, the difference was statistically significant (P<0.05). Conclusions CD16⁺ CD56⁺ NK cells were the earliest lymphocyte subsets reconstructed after allo-HSCT in children. NK cell reconstitution is closely related to the occurrence of aGVHD after allo-PBSCT, which may be used as an effective predictor of prognosis in patients with aGVHD.