摘要目的:探讨减低强度化疗方案治疗儿童唐氏综合征相关髓系白血病（ML-DS）的疗效和安全性。方法:回顾性分析2016年1月至2019年6月福建医科大学附属协和医院初诊并予美国儿童肿瘤协作组A2971方案规范化疗的3例ML-DS患儿的临床资料，总结其临床特征、疗效及安全性。结果:3例ML-DS患儿年龄分别为1岁6个月、2岁6个月及1岁10个月，2例为急性单核细胞白血病，1例为急性巨核细胞白血病；2例EVI1基因阳性，1例ASXL1基因突变，3例均为复杂核型。3例均在诱导化疗1个疗程后达完全缓解，微小残留病转阴。在诱导化疗中，3例均出现严重骨髓抑制，其中2例合并重症肺炎，1例合并肠道感染、感染性休克。结论:ML-DS患儿接受减低强度化疗效果较好，但需注意严重骨髓抑制及感染等并发症。

abstractsObjective:To investigate the efficacy and safety of reduced-intensity chemotherapy in treatment of children with Down syndrome-related myeloid leukemia (ML-DS).Methods:The clinical data of 3 hospitalized children with ML-DS who were diagnosed and treated by Children Oncology Group Trial A2971 chemotherapy regimen in Fujian Medical University Union Hospital from January 2016 to June 2019 were retrospectively analyzed, and the clinical characteristics, efficacy and safety were summarized.Results:The ages of 3 children were 1 year and 6 months, 2 years and 6 months, and 1 year and 10 months. Two cases were acute monocytic leukemia, and 1 case was acute megakaryoblastic leukemia. Two cases were positive for EVI1 gene and 1 case had ASXL1 gene mutation, and all 3 cases had complex karyotype. After one course of induction chemotherapy, all 3 cases achieved complete remission, and the minimal residual disease turned negative. During the induction chemotherapy, all 3 cases had severe myelosuppression, and 2 cases of them suffered from severe pneumonia and 1 case of them suffered from intestinal infection and septic shock.Conclusion:The efficacy of reduced-intensity chemotherapy in children with ML-DS is favorable, but the severe complications such as myelosuppression and infection need to be taken seriously.