急性淋巴细胞白血病患儿T细胞受体γ基因重排的检测及临床意义

Detection of Clonal T Cell Receptor γ Gene Rearrangement in Children with Acute Lymphoblastic Leukemia and Its Clinical Significance

目的探讨儿童ALL患者初诊时T细胞受体γ(TCRγ)基因的重排方式,病程中是否发生了克隆演化,并探讨其临床意义。方法选择2004年9月-2007年9月在广西医科大学第一附属医院儿科确诊的ALL患儿70例。男51例,女19例;平均年龄8.5(2～14)岁。采用酚/酚-异戊醇-氯仿/异戊醇法从骨髓细胞或静脉血细胞中提取DNA。通过多聚酶链反应及单链构象多态性分析,确定ALLTCRγ基因的重排方式。结果70例中23例初诊时检测出TCRγ基因重排。23例中10例完全缓解时仍可检出TCRγ基因重排,且对化疗药物敏感性差。23例中4例存在寡/亚克隆重排。23例中2例存在克隆演化,预后欠佳。结论病程中TCRγ基因的重排方式反映了白血病细胞的不断演化。发生演化的寡/亚克隆在缓解期持续存在,并进一步增殖从而导致临床复发。通过TCRγ基因的检测对ALL患儿的预后、复发的判断及制定相应的个体化治疗方案有重要的指导意义,可使患儿最大程度的达到长期无病生存,减少化疗导致的远期不良反应。

Objective To investigate the clonal rearrangement of T cell receptor （TCR） γ gene which was of monoclonality, oligoclonality or clonal evolution/subclonality during the course of disease in patients with acute lymphoblastic leukemia （ALL） and its significance. Methods Between Sep. 2004 and Sep. 2007,70 patients with ALL were diagnosed in Department of Pediatrics of the First Affiliated Hospital of Guangxi Medical University, among which 51 cases were boys and 19 cases were girls. Their ages ranged from 2 years to 14 years （average age was 8.5 years）. DNA samples were extracted from bone marrow cells or venous blood ceils by phenol/phenol - isoamyl alcohol - chloroform/isoamyl alcohol law. DNA was amplified by polymerase chain reaction （PCR）. Single strand conformation polymorphism analysis （SSCP） of silver stained technique was employed to detect PCR products. Results The amplification products of 23 cases of the 70 ALL patients were positive,in which 10 cases still had positive results in period of complete remission and had poor sensitivity to chemotherapeutic drugs,4 cases were of oligoclonality/subclonality, and 2 cases were of clonal evolution with poor prognosis. Conclusions Detecting TCR γ gene rearrangement reflects clonal evolution of leukemia cells. The oligoclonality clonal evolution continues to exist, whose multiplication is the main reason of recurrent ALL. Detecting TCRγ gene rearrangement, evaluating ALL of the patient＇s prognosis, the judgment of recurrence and the development of individualized treatment programs have great guiding significance ,which can maximize the possibility of the sick children to make long - term disease - free survival and reduce the side effects of chemotherapy on the long - term basis.