CML患者外周血TCR Vδ亚家族T细胞的谱系变化研究

目的 了解慢性粒细胞白血病(chronic myeloid leukemia,CML)患者慢性期(chronic phase,CP)和缓解期(complete remission,CR)外周血T细胞受体(T cell receptor,TCR)Vδ亚家族T细胞的分布和克隆性情况.方法 利用RT-PCR扩增8例CML-CP和8例CML-CR患者外周血T细胞中8个Vδ亚家族基因的互补决定区(CDR3),了解TCR Vδ亚家族T细胞的分布和利用情况;阳性产物进一步经基因扫描分析CDR3长度,从而了解其克隆性.10例健康人外周血作为对照.结果 8例CML-CP患者外周血T细胞平均表达(3.25±0.89)个Vδ亚家族,主要以Vδ1、Vδ2和Vδ3的表达为主,而8例CR期患者则平均表达(3.50±0.76)个Vδ亚家族,主要集中在Vδ1、Vδ2、Vδ3和Vδ8中表达;两组与健康对照组(3.50±0.52)比较无统计学意义.此外,Vδ8表达频率在CML-CR患者(5/8)中略高于健康人(3/10)和CML-CP患者(2/8).基因扫描绝大多数患者和健康人外周血TCR Vδ亚家族T细胞均存在克隆性增殖现象,主要以Vδ1-Vδ3为主,但在CML-CR患者中,表达V87亚家族的两例样本均呈克隆性增殖,这在10例健康人中均未检测到.结论 3组样本的外周血T细胞中TCR Vδ谱系和克隆性增殖类似,提示CML患者T细胞免疫抑制可能并不主要累及TCR Vδ谱系变化,并在CML-CR期所出现了一些不同的Vδ表达和克隆模式.

Changes in pattern of TCR Vδ repertoire in peripheral blood from CML patients

Objective To investigate the distribution and clonality of TCR Vδ repertoire T cells in periph-eral blood mononuclear cells with chronic myeloid leukemia (CML) at chronic phase (CP) and complete remis-sion (CR). Methods The CDR3 of TCR Vδ 8 subfamily genes were amplified in mononuclear cells of periph-eral blood from CML patients in CP (8 cases) and CR (8 cases) phases for observation of the usage of TCR Vδ repertoire by RT-PCR. The positive PCR products were further labeled with fluorescence and analyzed by genes-can technique for the CDR3 size for evaluation of the clonality of the detectable TCR Vδ T cells. A total of 10 eases of healthy adults served as controls. Results The mean values of detectable TCR Vδ subfamilies were (3.25±0.89) in patients with CML-CP, predominantly in Vδ1, 2 and Vδ3, whereas (3.5±0.76) of 8 Vδ subfamily T cells were expressed in patients with CML-CR, predominantly in Vδ1,2, 3 and Vδ8. There was no significant difference between the above groups and the healthy adults (3.5±0.52). In addition, a higher fre-quency expression of Vδ8 could be found from peripheral blood in CR phase (5/8) rather than from that in CP phase (2/8) and from that of the healthy adults (3/10). Genescan analysis showed that the majority of PCR products from both CML and healthy adults displayed clonal expansion, predominantly in Vδ1, Vδ2 and Vδ3. Clonal expanded Vδ7 subfamily T cells, however, could be identified from two patients in CR phase but not in all of 10 healthy adults. Conclusion The similar distribution and clonal pattern of TCR Vδ repertoire T cells can be found in peripheral blood from the three groups, suggesting that the cellular immunosuppression of CML patients might not be mainly involved in the alteration of TCR Vδ repertoire. In CML-CR groups, the expression and clonal pattern of some Vδ repertoires are different from those in other groups, which needs further studies.