儿童系统性肥大细胞增生症伴急性髓系白血病造血干细胞移植后随访2例分析

Hematopoietic stem cell transplantation for systemic mastocytosis associated with acute myeloid leukemia in children:a clinical follow-up of 2 cases

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7.69×10^(8)/kg,CD3^(4+)细胞计数1.31×10^(5)/kg1例;回输单个核细胞数9.08×10^(8)/kg,CD3^(4+)细胞计数为6.81×10^(6)/kg 1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)(q 22;q 22)and AML1-ETO fusion gene was positive.The variation of KIT V 560 D(exon 11)was found in one child,and the variation of KIT T 418_D 419 del(exon 8),KIT N822K(exon 17),and NRAS G 13 D(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 7.69×10^(8)/kg and the number of returned CD 3^(4+)cells was 1.31×10^(5)/kg in one patient.The number of mononuclear cells was 9.08×10^(8)/kg and the number of returned CD 3^(4+)cells was 6.81×10^(6)/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.