肾移植患者外周血人巨细胞病毒特异性CD8^＋T淋巴细胞频率及其γ干扰素分泌功能的初步研究

A primary study on the level of human cytomegalovirus specific CD8^＋ T lymphocytes and IFN-γ secretion effect in kidney transplant recipients

目的研究肾移植患者外周血人巨细胞病毒（HCMV）特异性细胞毒T淋巴细胞（CTL）的频率及其γ干扰素（IFN-γ）分泌功能，以期探讨HCMV活化感染的免疫学机制。方法选取HCMV血清学阳性的HLA-A^＊0201肾移植患者和健康对照者，将其分为3组：存在HCMV活化感染的肾移植组（9例）、无HCMV活化感染的肾移植组（29例）和健康对照组（54名）；运用HLA-A2-NLVPMVATV．五聚体检测外周血中总的HCMVNLVPMVATV特异性CTL，同时以NLVPMVATV体外刺激PBMC，检测IFN-γ分泌性CTL。结果在健康对照组、无HCMV活化感染的肾移植组和存在HCMV活化感染组中，HCMV特异性CTL频率中位数分别为1．19％（0～19．42％）、1．20％（0～18．40％）和3．2％（0．51％～18．90％），差异无统计学意义（H=5．34，P〉0．05）；IFN-γ分泌细胞频率中位数分别为0．72％（0-0．70％），0．47％（0-5．61％）和0．67％（0．07％-4．00％），差异无统计学意义（H=0．58，P〉0．05），但HCMV特异性CTL中IFN-γ分泌细胞的比例分别为（60．18±19．16）％，（39．19±17．22）％和（20．02±13．26）％，组间比较差异有统计学意义（P〈0．01）。结论肾移植组外周血中HCMVNLVPMVATV特异性CTL频率较健康对照组并无降低，但其分泌IFN-γ的比例降低，出现HCMV活化感染组IFN-γ分泌CTL比例降低更为明显。HCMV特异性CTL的IFN-γ分泌功能受损可能是造成肾移植患者HCMV活化感染的因素之一。

Objective To investigate the level of human cytomegalovirus （HCMV） specific CDs＋ T lymphocytes in peripheral blood and the immune response of HCMV reactivation after kidney transplantation. Methods Thirty-eight HCMV seropositive HLA-A^＊ 0201 kidney transplant recipients （9 with HCMV infection and 29 without HCMV infection） and 54 healthy individuals were enrolled. The levels of total HCMV specific CDs＋ T cells were measured using HLA-A2 pentamer folded with HCMV- peptide NLVPMVATV. The levels of IFN-γ secreting CDs＋ T cells were measured by intracellular IFN-γ staining pulsed with the same peptide. Results The median levels of pentamer stained CD8^＋ T cells were 1.19% （0-19.42%）, 1.20% （0-18.40%） and 3.2% （0.51%-18.90%） in healthy group, negative HCMV group and positive HCMV group （ H = 5.34, P 〉 0. 05 ）, respectively. The median levels of IFN-γ secreting CDs＋ T cells were 0.72% （0-0.70%）, 0.47% （0-5.61%） and 0.67% （0.07%-4.00%）, respectively （H = 0. 58,P 〉 0. 05 ）. However, the mean proportions of IFN-γ secreting pentamer stained T cells relative to total HCMV specific CTL were （60. 18 ± 19. 16） %, （39. 19 ± 17. 22） % and （20. 02 ± 13. 26） %, respectively. There were significant differences among the groups （ P 〈 0.01 ）. Conclusions There was no significant difference of levels of HCMV specific CD8^＋ T lymphocytes in peripheral blood between the kidney transplant recipients and healthy individuals. However, the proportion of HCMV-specific IFN-γ producing CD8^＋ T cells in pentamer stained cells was reduced in the kidney transplant recipients especially in those with active HCMV infection, which may contribute to the inability to control HCMV reactivation.