特发性血小板减少性紫癜患者外周血T细胞Fas-FasL和caspase-3凋亡相关蛋白的表达及其意义

目的 探讨Fas、FasL及caspase-3凋亡相关蛋白在特发性血小板减少性紫癜(ITP)患者T淋巴细胞的表达及其意义.方法 应用流式细胞术测定T细胞亚群表面Fas、FasL的表达率及细胞质中活化caspase-3的表达率,用Western blot法检测T细胞亚群caspase-3蛋白的表达.结果 与健康对照组[(29.4±8.2)%]相比,ITP患者组CD4+ T细胞表面Fas的表达率显著增加[(42.1±9.5)%](P＜0.05),CD8+ T细胞表面Fas的表达率略有增加但差异无统计学意义[(9.3±6.0)%与(13.4±5.8)%](P＞0.05).ITP患者组T细胞亚群表面FasL的表达率均较健康对照组显著增加(P＜0.05).ITP患者组T细胞亚群胞质中活化caspase-3的表达率,明显高于健康对照组(P＜0.05).Western blot检测结果显示,与治疗前相比,ITP患者治疗后CD4+ T细胞表达pro-caspase-3和cleaved-caspase-3均明显减少(P＜0.05).结论ITP患者外周血T细胞Fas、FasL及caspase-3表达明显增加,激素治疗可干预Fas-FasL、caspase-3的表达水平,提示Fas、FasL及caspase-3信号通路在ITP发生机制中起一定作用.

Fas-FasL and caspase-3 signal transduction pathway and apoptosis of peripheral T lymphocytes in ITP patients

OBJECTIVE: To explore the relationship between Fas-FasL-mediated signal transduction pathway and apoptosis of T lymphocyte subset in ITP patients. METHODS: The expression rates of membrane Fas, FasL and intracellular activated caspase-3 in peripheral T lymphocyte subset were determined by flow cytometry. T cell subsets with caspase-3 protein expression were detected by Western blot. RESULTS: As compared with that in healthy control group [(29.4 +/- 8.2)%], the expression rate of membrane Fas on CD4+ T cells was significantly increased in ITP patients [(42.1 +/- 9.5)%] (P < 0.05), however, that on CD8+ T cells was only slightly increased [(9.3 +/- 6.0)% vs (13.4 +/- 5.8)%] with no statistical significance (P > 0.05). The expression rate of FasL on T cell subset in ITP patients was significantly increased (P < 0.05), and that of intracellular activated caspase-3 in T cell subset in ITP patients was notably higher than that in healthy control group (P < 0.05). Western blot analysis showed that the expression of pro-caspase-3 and cleaved-caspase-3 in CD4+ T cells in patients with ITP after treatment were significantly reduced compared with those before treatment (P < 0.05). CONCLUSION: Apoptosis of T lymphocyte subset in ITP patients is accelerated. It is possible that Fas-FasL signal transduction pathway plays an important role in the induction of the apoptosis. The degree of apoptosis of T lymphocytes closely correlates with the disease's activity in ITP patients. Hormone therapy may interfere with Fas-FasL signal transduction pathway of apoptosis.