T淋巴细胞亚群异常与特发性血小板减少性紫癜的关系

目的 通过检测T淋巴细胞亚群及其凋亡，初步探讨T淋巴细胞亚群异常在特发性减少性紫癜（ITP）发病机制中的作用。方法 采用流式细胞术对ITP患者及正常对照组的外周血淋巴细胞亚群进行检测；DNA琼脂糖凝胶电泳检测T淋巴细胞的凋亡。结栗ITP患者CD3^＋、CD4^＋和CD4^＋CD25^＋T细胞比例均显著低于正常对照组（P〈0．05或P〈0．01），而CD8^＋T细胞和CD4^＋T细胞表面Fas表达均较正常组增加（P〈0．01）；T淋巴细胞凋亡敏感性增加。结论 ITP患者外周血T淋巴细胞亚群异常，T细胞免疫调控亚群（CD4^＋CD25^＋）凋亡增多，对自身反应性T细胞亚群免疫下调作用降低，破坏自身免疫耐受，在ITP的发病中起重要作用。

Relationship Between the Abnormal T Lymphocyte Subsets and Idiopathic Thrombocytopenic Purpura

Objective To study the role of T lymphocytes in the pathogenesis of idiopathic thrombocytopenic purura(ITP) via investigation of the phenotype and apoptosis of T lymphocytes. Methods Heparinized peripheral blood collected from patients with ITP and normal controls were phenotyped by FACS.DNA fragments were tested by agarose gel electrophoresis. Results The percentage of CD~+_3 and CD~+_4 and CD~+_4CD~+_(25)T cells in ITP patients was significantly lower than those in normal controls(P<0.05 or P<0.01),but the percentage of CD~+_8T cells and the expression of Fas on CD~+_4 T cells was much higher(P<0.01).Susceptibility to apoptosis of T lymphocytes in ITP patients was increased. Conclusion Aberrant lymphocyte phenotypes were demonstrated in ITP patients.The CD~+_4CD~+_(25)immunoregulatory T cells subset was decreased significantly in ITP patients,resulting in defective suppression of the autoreactive T cells and leading to the breakdown of immune tolerance.So T lymphocytes play a critical role in in the pathogenesis of ITP.