2岁以下婴幼儿急性淋巴细胞白血病41例

目的总结2岁以下婴幼儿急性淋巴细胞白血病（ALL）的生物学特征。方法回顾性分析1996年1月至2005年12月在北京儿童医院诊治的2岁以下ALL患儿的临床资料及治疗效果，随访至2006年8月31日。结果共41例患儿，占同期ALL的3．9％。诊断后治疗者28例。诊断时年龄≤12个月11例，白细胞数大于20×10^9／L21例，中枢神经系统侵犯者5例，骨髓免疫学均为B细胞来源，其中带有髓系标志22例，17例存在染色体易位，其中7例为11q23易位形成的融合基因。诊断后治疗的患儿，于诱导治疗第28天骨髓完全缓解率100％，复发4例，复发时间为缓解后9—34个月（中位14个月），4例复发患儿均为高白细胞，且3例具有11q23形成的融合基因。22／28例患儿生存并随访至今，随访时间8～124个月（中位39个月）；持续完全缓解时间1～124个月（中位36．5个月）。结论2岁以下婴幼儿ALL的生物学特点明显，临床多表现为高白细胞，骨髓免疫学以B细胞型为主，且髓系相关抗原联合表达的频率很高，染色体以11q23易位形成的融合基因为多见，骨髓复发仍然是治疗失败的重要原因，伴有11q23易位形成的融合基因者预后差。

Analysis of 41 cases at the age less than 2 year old with acute lymphoblastic leukemia

Objective Repots of the clinical feature,immunophenotype and cytogenetic trait for children at age of less than 2 year old with newly diagnosed acute lymphoblastic leukemia(AEL).MethodsBetween 1996.1～2005.12 in Beijing Children's Hospital. children less than 2 year old with ALL were enrolled.Using retrospective methods,we collected and studied the clinical data,following up till to August 31.2006.Results There were 41 children with ALL at age of less than 2 year old.accounting for 3.9% of allin the same time,including 11 for the age less than 12 months old,21 with WBC more than 20×109/L 5 with center nervous system(CNS)leukemia.All cases are B-cell immunophenotype,22 with immunophenotypic co-expression of myeloid associated antigens,17 cytogenetic abnormalities and fusion gene positive,among them,7 involving ALL-1/MLL 11q23 gene rearrangements.Among 41 cases.28 cases were given combined intensive chemotherapy and achieved complete remission(CR)with induction therapy for 28 days,4 cases were relapsed from CR 9～34 months(medium 18 months).22 cases were follow-up continuously during 8 to 124 months(medium 39 months),continue complete remission(CCR)from 1 to 124 months(medium36.5 months).Conclusion Children with ALL at the age less than 2 year old display unique biological features as compared with older children.is associated with a hish leukocyte count at presentation and CNS involvement. The immunophenotype is usually B-lineage and is characterized by the co-expression of myeloid-associated antigens. and presence of involving ALL-1/MLL 11q23 gene rearrangements. Marrow relapse remains the primary mode of failure. Cytogenetic abnormalities involving ALL-1/MLL 11q23 gene rearrangements with ALL have a very poor outcome.