类风湿性关节炎患者外周血CD4^+T细胞存在凋亡缺陷

Impaired apoptosis of peripheral blood CD4^+ T cells in patients with rheumatoid arthritis

目的探讨CD4+T细胞凋亡在类风湿性关节炎(RA)发病机制中的作用。方法 30例RA患者和12例健康对照者分为2组,应用annexinⅤ-FITC/PI双标记结合流式细胞术分析RA患者及对照者CD4+T细胞凋亡水平,实时定量PCR(qRT-PCR)检测凋亡相关蛋白Fas、Fas L、caspase-8、caspase-3、Bcl-2、Bax mRNA相对表达水平,Western blot法测定细胞凋亡蛋白Fas、Fas L及caspase-8、caspase-3的表达;分析RA组凋亡蛋白表达水平与临床活动指标的相关性。结果与健康对照组相比,RA患者CD4+T细胞凋亡减少;与血沉(ESR)、类风湿因子(RF)呈负相关;qRT-PCR结果表明,RA患者CD4+T细胞Fas、caspase-8、caspase-3、Bax mRNA的表达量显著降低、Bcl-2 mRNA表达量增加。Fas表达与中医症状积分呈负相关,Bcl-2与环瓜氨酸肽(CCP)水平呈正相关。Western blot结果显示,RA患者CD4+T细胞Fas、Fas L、caspase-8、caspase-3的表达量较正常组明显降低,Fas与CRP呈正相关、Fas L与晨僵时间呈负相关。结论 RA患者外周血CD4+T淋巴细胞凋亡减少,与多数相关凋亡蛋白的表达降低、Bcl-2表达增强有关。提示RA存在凋亡缺陷,Fas介导的细胞凋亡在RA过程中有一定作用。

Objective To investigate the role of CD4 ＋T cell apoptosis in the pathogenesis of rheumatoid arthritis （RA）. Methods The study enrolled 30 RA cases and 12 normal individuals as subjects. The apoptosis level of CD4 ＋T lymphocytes in the patients with RA and the control individuals were measured by annexin V-FITC/PI staining combined with flow cytometry. The expression levels of Fas, FasL, caspase-8, caspase-3, Bcl-2 and Bax mRNAs were detected using real-time quantitative PCR （qRT-PCR） ; the expressions of Fas, FasL, caspase-8, caspase-3 proteins were observed using Western blotting. The correlations between the expressions of the apoptosis-related proteins and the clinical activity parameters were analyzed. Results The apoptosis level of CD4 ＋ T lymphocytes in RA patients was significantly lower than that in the healthy controls, and it was negatively correlated with erythrocyte sedimentation rate （ESR） and rheumatoid factor （RF）. Compared with the healthy control group, the expression levels of Fas, FasL, caspase-8, caspase-3 and Bax mRNAs in CD4 ＋ T cells of the RA patients were significantly reduced, whereas Bcl-2 mRNA was significantly elevated. The expression of Fas mRNA in CD4 ＋ T cells was negatively correlated with traditional Chinese medicine symptom score, whereas Bcl-2 mRNA was positively correlated with cyclic citrullinated peptide （CCP）. Compared with the control group, the expressions of Fas, FasL, caspase-8 and caspase-3 proteins in CD4 ＋ T cells in the RA patients significantly decreased. The expression level of Fas protein was positively correlated with C-reactive protein （CRP）, whereas FasL was negatively correlated with the time of morning stiffness. Conclusion There is a decrease in the apoptosis of peripheral blood CD4＋ T cells in patients with RA, which has been found related to the decreased expressions of the apoptosis-related proteins （Fas, FasL, caspase-8, caspase-3, Bax） and the increased expression of Bcl-2. The study suggests that Fas-mediated apoptosis plays a role in the development of RA.