协同刺激分子CD28/CTLA-4:B7在胃癌患者中的表达及临床意义

目的研究胃癌患者外周血共刺激分子CD28和细胞毒性T淋巴细胞相关抗原-4（CTLA-4，CD152）及B7分子的表达水平，以探讨胃癌患者共刺激通路是否异常以及在胃癌发病机制中的作用。方法用流式细胞仪检测56例胃癌患者外周血淋巴细胞表面的CD28、CD152、CD3、CD4、CD8及B7分子的表达，并与健康对照组及胃良性肿瘤组作比较。结果胃癌患者外周血中CD3^＋、CD4^＋、CD3^＋CD28^＋、B7-1（CD80）、B7～2（CD86）的表达水平及CD4^＋／CD8^＋低于健康对照组及良性肿瘤组，CD3^＋、CD152^＋和CD8^＋水平显著增高。结论胃癌患者外周血淋巴细胞低表达CD28和B7分子，高表达CTLA-4分子，导致了胃癌患者B7：CD28／CTLA-4共刺激通路异常，影响了T细胞彻底清除肿瘤细胞，从而使肿瘤逃避机体的免疫监视、免疫抑制，发生转移。

Expressions of CD28/CTLA-4:B7 co-stimulatory molecules in patients with gastric cancer and its clinical significance

Objective To investigate.the co-stimulatory pathway of gastric cancer patients by examining the expression of co-stimulatory molecules CD28,CTLA.4(CDl 52)and B7 molecules on peripheral blood lymphocytes(PBLC)in patients with gastric cancer,and to discuss the role of costimulatory pathway in the pathogenesis of gastric cancer.Methods The expression of CD28,CD152,CD3,CD4,CD8 and B7 molecules on peripheral blood lymphocytes and T cell subpopulation were measured by flow cytometry in 56 patients with gastric cancer,and the data was compared and analyzed with that in gastric benign tumor group and healthy control group.Results The expression levels of CD3+,CD4+,CD3+ CD28+,B7-1(CD80),B7-2(CD86)and CD41/CD8+on PBLC in patients with gastric cancer was significantly lower than that of benign stomach tumor group and healthy control group.The expression levels of CD3+ CDl52+ and CD8+ on PBLC in patients with gastric cancer were significantly higher than those of gastric benign tumor group and healthy control group.Conclusion Peripheral lymphocytcs in gastric cancer patients express low level of CD28 and B7 molecules and high level of CDI 52 molecules,which results in dysfunction of B7:CD28/CTLA-4 co-stimulation pathway and in turn affects the capacity of T cell to eliminate tumor cells,which makes tumor cells evading the immune surveillance and metastasizing.