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

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

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。

AIM： To investigate the distribution and clonal expansion of 29 T cell receptor （TCR） Vet 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 Vet subfamily T cells. 9 normal individuals served as control. RESULTS ： Most Vet subfamily genes could be detected in PBMCs from normal individuals, whereas only 1 - 10 subfamily T cells were identified in 8 cases with AML - MS, the highest frequently expressed Vet subfamily was Vα3 （75%）, and Vα12 was the second （62. 5% ）, 15 Vet 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 Vet subfamily T cells. CONCLUSION： The selected usage and clonal expansion of TCR Vet subfamily T cells from peripheral blood could be found in patients with AML - MS. It may be a specific immune response which the host T cells are activated by the M5 leukemia cells. The distribution pattern of Vet subfamily clonal expansion displays individual specificity.