目的 探讨造血干细胞移植（HSCT）治疗儿童系统性肥大细胞增生症伴急性髓系白血病（SM-AML）的疗效及治疗后的临床随访情况。方法 回顾分析2例经HSCT治疗SM-AML患儿的临床资料及随访结果，并复习相关文献。结果 2例患儿，男1例、女1例，年龄2岁、9岁。2例首发症状均为发热伴血常规异常，骨髓涂片细胞学检查为原始粒细胞增多，梭形或非典型肥大细胞增多。t(8;21)(q22;q22)染色体易位阳性，AML1-ETO融合基因阳性。基因变异KIT V560D（外显子11）1例，KIT T418_D419del（外显子8），KIT N822K（外显子17），NRAS G13D（外显子2）1例。诊断为SM-AML后按CCLG-AML 2019方案给予诱导化疗及巩固化疗。化疗后复查骨髓涂片细胞形态学均为AML完全缓解，肥大细胞增多（6.6%~27.6%）。无关HLA不全相合（9/10）脐血HSCT 1例，预处理方案为氟达拉滨+白消安+环磷酰胺。亲缘HLA不全相合（9/10，姐供妹）HSCT 1例，预处理方案为阿糖胞苷+白消安+环磷酰胺+福莫司汀+抗胸腺球蛋白。回输总有核细胞数7.69×10⁸/kg ，CD34⁺细胞计数1.31×10⁵/kg1例；回输单个核细胞数9.08×10⁸/kg，CD34⁺细胞计数为6.81×10⁶/kg1例。2例SM-AML患儿的造血功能均获得重建，移植后中性粒细胞植入时间11~27 d，血小板植入时间13~47 d。随访至2022年8月，2例患儿均存活，1例肥大细胞及AML1-ETO融合基因均转阴，1例肥大细胞持续存在，AML1-ETO融合基因仍为阳性。结论 HSCT治疗SM-AML可行，移植前化疗方案以及关键性移植问题值得进一步研究。

Objective To investigate the efficacy and the clinical follow-up of hematopoietic stem cell transplantation (HSCT) for systemic mastocytosis associated with acute myeloid leukemia (SM-AML) in children. Methods The clinical data and follow-up results of 2 children with SM-AML treated by HSCT were retrospectively analyzed, and the related literature was reviewed. Results There were 2 children (1 boy and 1 girl) with SM-AML, aged from 2 to 9 years. The onset symptom of 2 cases was fever with abnormal blood image, and bone marrow smear cytology showed increased myeloblasts and spindle or atypical mastocytosis. The karyotype of t(8;21)(q22;q22) and AML1-ETO fusion gene was positive. The variation of KIT V560D (exon 11) was found in one child, and the variation of KIT T418_D419del (exon 8), KIT N822K (exon 17), and NRAS G13D (exon 2) were found in another child. After diagnosis of SM-AML, induction chemotherapy and consolidation chemotherapy were given according to CCLG-AML 2019 regimen. Bone marrow smear morphology after chemotherapy showed complete remission of AML and increased mast cells (6.6%-27.6%). One patient was treated with HSCT from HLA-mismatched unrelated umbilical cord blood donor (9/10), and the pretreatment regimen was fludarabine + busulfan (Bu) + cyclophosphamide (CTX). One patient was treated with HSCT from HLA-mismatched sibling donor (9/10, elder sister donor), and the pretreatment regimen was cytarabine + Bu + CTX+ fotemustine + antithymocyte globulin. The number of returned nuclear cells was 7.69×10⁸/kg and the number of returned CD34⁺ cells was 1.31×10⁵/kg in one patient. The number of mononuclear cells was 9.08×10⁸/kg and the number of returned CD34⁺ cells was 6.81×10⁶/kg in another patient. Hematopoietic function was reconstructed in 2 children with SM-AML. The time of neutrophils engraftment and platelet engraftment after transplantation were 11-27 d and 13-47 d, respectively. Two patients were followed up until August 2022, and they both survived. Mast cells and AML1-ETO fusion gene turned negative in one patient. Mast cells persisted in another patient, and the AML1-ETO fusion gene was still positive. Conclusions HSCT is feasible for the treatment of SM-AML. The regimen of chemotherapy before transplantation and the key problems of transplantation are worthy of further study.