RQ-PCR检测Ig/TCR基因重排监测急性淋巴细胞白血病患儿治疗过程微小残留白血病

Clinical study on Ig/TCR gene rearrangement detection by RQ-PCR for monitoring minimal residual disease of childhood acute lymphoblastic leukemia

目的研究RQ-PCR检测急性淋巴细胞白血病(ALL)患儿Ig/TCR基因重排在微小残留白血病(MRD)监测中的作用。方法以2009年3月至2011年3月在广州市妇女儿童医疗中心血液肿瘤科确诊和治疗的ALL患儿为研究对象,PCR检测初诊ALL患儿的Ig/TCR基因重排;基因扫描分析初诊患儿Ig/TCR基因重排的克隆特性;对ALL患儿的单克隆性Ig/TCR基因重排进行测序,RQ-PCR检测不同治疗阶段Ig/TCR基因重排的表达量。结果 86例ALL患儿进入分析,男52例,女34例;年龄1～13(4.3±3.0)岁,随访时间1～26(14.3±7.0)个月。①83例(96.5%)检出1种或以上Ig/TCR基因重排,共检出209个Ig/TCR基因重排;②91.8%(56/61例)检出1种或以上单克隆性Ig/TCR基因重排;61例172个Ig/TCR基因重排中,单克隆性、寡克隆性和多克隆性Ig/TCR基因重排的检出率分别为58.1%(100个)、30.8%(52个)和11.0%(19个),差异有统计学意义(P=0.000);③26例完成连续3次随访,其中22例持续完全缓解患儿的Ig/TCR基因重排平均相对表达量持续下降,在维持治疗前均为MRD阴性(≤1.0×10-4);4例复发患儿在诱导缓解治疗后至复发前各检测时点Ig/TCR基因重排表达量均>1.0×10-4,并在复发前已有回升,从开始回升至临床复发的平均时间为3.75(2～8)个月。结论 Ig/TCR基因重排相对表达量可反映MRD水平,可作为判断预后、监测复发和指导治疗的有效手段。

Objective To evaluate the applied meaning of Ig/TCR gene rearrangements by RQ-PCR for minimal residual disease（MRD） detection in childhood acute lymphoblastic leukemia （ALL）.Methods ①PCR detection of Ig/TCR gene rearrangements of ALL children was performed at diagnosis. ②The clonality of Ig/TCR gene rearrangements was analyzed by GeneScan. ③The sequence of monoclonal PCR products was checked to determine the patient-specific sequence as MRD detection target followed by the design of patient-specific primers and probes, and RQ-PCR quantification at different therapy phases.Results Eighty six children diagnosed as ALL were included. ①At least one type of Ig/TCR rearrangement was found in 96.5% （83/86） ALL children. ②91.8% （56/61） ALL children were detected to have at least one monoclonal Ig/TCR gene rearrangement. The detection rates for monoclonal, oligoclonal and polyclonal Ig/TCR rearrangement were 58.1%, 30.8% and 11.0% with significant difference（P0.001）. ③For 22 continuous complete remission（CCR） cases, the Ig/TCR gene rearrangement expression consistently decreased as therapy continued, and before maintaining therapy, all tested MRD cases were detected to be MRD negative; For 4 relapse cases, MRD was persistently positive from beginning of induced remission to relapse, and clinically the average relapse time was 3.75 months （ranging from 2 to 8 months） since the relative expression of Ig/TCR rearrangement started increasing.Conclusions Surveillance of ALL children＇s MRD level detected by RQ-PCR with Ig/TCR gene rearrangement as targets, is a potentially useful assay for evaluation and assessment of therapy effect and relapse prediction.