HLA-G与肾移植术后巨细胞病毒活动性感染的相关性研究

目的 研究HLA-G与肾移植术后巨细胞病毒(CMV)活动性感染的相关性，分析其作用机制及意义。方法 初次肾移植受者215例，按照术后是否发生CMV活动性感染将受者分为CMV阳性组和CMV阴性组，采用流式细胞术检测膜结合型HLA-G1 (mHLA-G1)的表达，采用酶联免疫吸附试验检测可溶性HLA-G5 (sHLA-G5)的表达，采用逆转录聚合酶链法检测HLA-G mRNA的表达，采用蛋白质印迹法验证sHLA-G5的表达，采用免疫组织化学法和HE染色观察移植肾组织中HLA-G的表达，采用ROC曲线分析sHLA-G5水平预测CMV活动性感染的Cutoff值。结果 术前两组间HLA-G表达的差异无统计学意义(P＞0.05)。术后两组间外周血淋巴细胞表面mHLA-G1均呈低表达，CMV pp65阳性时亦无明显变化。CMV阳性组外周血中CD14+ mHLA-G1+细胞显著升高(P＜0.05)，达到(45.53±17.32)％，转阴后下降至(10.22±5.78)％。CMV阳性组外周血中sHLA-G5表达水平明显升高(P＜0.05)，其预测CMV活动性感染的最适Cutoff值为202.9μg/L，具有很高的诊断准确性。CMV阳性组受者外周血中HLA-G mRNA的表达水平均显著高于CMV阴性组(P＜0.05)。12例CMV活动性感染受者移植肾活检样本中，10例肾小管上皮细胞HLA-G表达呈阳性。结论 HLA-G在外周血中的表达显著升高和移植肾肾小管上皮细胞的阳性表达可能是保护移植肾功能的机制之一。以sHLA-G5表达水平202.9μg/L作为Cutoff阈值，具有很好的判断CMV活动性感染的价值。

Correlation of HLA-G expression with CMV active infection following kidney transplantation

Objective To determine the correlation of human leukocyte antigen-G (HLA-G)expression with CMV active infection after kidney transplantation. Methods A total of 215 first-time kidney transplantation recipients in one transplantation center were divided into CMV ( + ) group and CMV ( - ) group according to whether they had active CMV infection. mhla-g1 expression on leukocytes was analyzed by flow cytometry. The concentrations of soluble HLA-G5 were detected by using ELISA. The sHLA-G5 cutoff levels by ROC curve was employed to predict the active CMV infection. The expression of sHLA-G5 mRNA and protein in leukocytes was analyzed by using RTPCR and Western blotting respectively. Immunohistochemical staining was used to detect the HLA-G expression in kidney biopsies of 12 cases. Results The expression of mHLA-G1 in peripheral blood was low in both CMV ( + ) group and CMV ( - ) group. Also when CMV-PP65 was positive, there was no significant change in mHLA-G1. In CMV ( + ) group, the proportion of CD14+ mHLA-G1 +cells[(45. 53 ± 17.32)％]in peripheral blood was increased as compared with that in CMV (-)group[(10. 22 ± 5.78)％]. The expression of sHLA-G5 was increased significantly in CMV ( + )group. The optimal cutoff value of sHLA-G5 predicting the active CMV infection was 202. 9 μg/L,with high diagnostic accuracy. HLA-G was positive in the kidney tissue of 10 patients out of 12 patients with active CMV infection. Both RT-PCR and Western blot analysis showed that sHLA-G5 was significantly higher in CMV ( + ) group than that in CMV ( - ) group. Conclusion ROC curve analysis of sHLA-G5 with the cutoff value of 202. 9 μg/L can be used to predict the active CMV infection. The HLA-G levels in peripheral blood were significantly increased and HLA-G expression in the tubular epithelial cells of the graft could be a protection mechanism of the kidney function.