急性单核细胞白血病病人外周血TCR Vα基因谱系和T细胞克隆性增殖特点

目的：了解急性单核细胞白血病（AML-M5）病人TCR Vα29个亚家族的分布及其克隆性。方法: 利用RT-PCR分别扩增8例M5病人外周血单核细胞的TCR Vα29个亚家族基因的CDR3。阳性的PCR产物进一步经荧光素标记和基因扫描分析产物的CDR3长度，了解T细胞克隆性。9例健康人作为对照。结果: RT-PCR分析显示正常人表达绝大多数Vα亚家族基因，而8例M5病人外周血仅可以检测到1-10个Vα亚家族基因，出现频率最高的是Vα3（6/8例，75%），其次为Vα12（5/8例，62.5%），有15个Vα亚家族表达缺失（Vα1、4、5、7、9、14-18、20、21、26、28和Vα29）。基因扫描分析显示：8例AML-M5病人中有6例存在克隆性增殖T细胞，其中，以Vα12亚家族出现克隆性增殖T细胞频率（3/5例）最高，有2例仅存在单一的克隆性增殖Vα3亚家族T细胞。正常人外周血各Vα亚家族T细胞主要呈多克隆性。结论: M5病人外周血Vα亚家族T细胞存在明显的选择性选用及克隆性增殖特点，这可能是机体T细胞受M5细胞刺激而引起机体产生相应的特异性免疫反应，同时T细胞TCR Vα亚家族分布及克隆性增殖情况具有个体特异性。

The feature of TCR Vα repertoire and clonal expansion of T cells from peripheral blood in patients with acute monoblastic leukemia

AIM: To investigate the distribution and clonal expansion of 29 T cell receptor (TCR) Vα subfamily T cells in patients with acute monoblastic leukemia (AML-M5)．METHODS: The CDR3 of TCR Vα 29 subfamily genes were amplified in peripheral blood mononuclear cells (PBMCs) from 8 cases with AML-M5 using RT-PCR，and the PCR products were further labeled with fluorescent and analyzed by genescan technique for the CDR3 size,to evaluate clonality of the detectable TCR Vα subfamily T cells.9 normal individuals served as control.RESULTS: Most Vα subfamily genes could be detected in PBMCs from normal individuals,whereas only 1-10 subfamily T cells were identified in 8 cases with AML-M5,the highest frequently expressed Vα subfamily was Vα3 (75%),and Vα12 was the second (62.5%),15 Vα subfamilies (Vα1,4,5,7,9,14-18,20,21,26,28 and Vα29) were absent.Genescan analysis showed that clonal expanded T cells were found in T cells from 6 out of 8 AML-M5 cases.The highest frequency of clonal expanded T cells predominated in Vα12 (3 out of 5 positive samples).In PBMCs from two cases,clonal expanded Vα3 T cells were the unique detectable Vα subfamily T cells.CONCLUSION: The selected usage and clonal expansion of TCR Vα subfamily T cells from peripheral blood could be found in patients with AML-M5.It may be a specific immune response which the host T cells are activated by the M5 leukemia cells.The distribution pattern of Vα subfamily clonal expansion displays individual specificity．