摘要目的 研究胸腺切除对重症肌无力(MG)患者外周血淋巴细胞(PBL)中Fas表达及T淋巴细胞亚群的影响,探讨胸腺切除术治疗MG与Fas介导的细胞凋亡的关系.方法 采用流式细胞技术检测17例MG患者及13例健康对照组PBL中CD4、CD8及Fas表达.结果 与对照组相比,无行胸腺切除术组MG患者PBL中CD4-CD8+细胞比例升高,CD4-CD8-细胞比例下降,差异有统计学意义(P＜0.05);行胸腺切除术组CD4-CD8+细胞比例较无行胸腺切除术组下降,差异有统计学意义(P＜0.05).无行胸腺切除术组MG患者PBL中Fas+、CD8+Fas+细胞比例以及行胸腺切除术组Fas+细胞比例均高于对照组,差异有统计学意义(P＜0.05).行胸腺切除术组MG患者PBL中Fas+、CD4+Fas+及CD8+Fas+细胞比例低于无行胸腺切除术组,但差异无统计学意义(P＞0.05).结论 MG患者存在外周血T淋巴细胞亚群分布异常,胸腺切除可减少此异常.MG患者PBL表面Fas表达升高,可能反映体内T淋巴细胞的活化及CD8+T淋巴细胞介导的细胞毒性作用增强.胸腺切除可降低PBL中Fas的表达,可能与治疗MG的机制有关.

abstractsObjective To investigate the influences of thymectomy on the Fas expression and T cell subsets in peripheral blood lymphocyte (PBL) from patients with myasthenia gravis ( MG), so as to make sure whether Fas-mediated apoptosis is involved in the mechanism of thymectomy in MG therapy. Methods We analyzed CD4 、CD8 and Fas expressions in PBL from 17 patients with MG and 13 healthy controls using flow cytometric analysis. Results The percentage of CD4-CD8+ cells in PB of MG patients without thymectomy was significant higher, while the percentage of CD4-CD8-8-cells was significant lower, compared with controls ( P ＜0. 05 ). The percentage of CD4-CD8 + cells in PBL of MG patients with thymectomy was significant lower than the ones without thymectomy( P ＜ 0. 05 ). The percentages of Fas + and CD8 + Fas + cells in PBL of MG patients without thymectomy, as well as the percentage of Fas + cells in PBL of MG patients with thymectomy, were significant higher than that of controls ( P ＜ 0. 05 ). The percentages of Fas + , CD4 + Fas + and CD8 + Fas + cells in PBL of MG patients with thymectomy were lower than the ones without thymectomy, but the differences were not significant ( P ＞ 0. 05 ). Conclusion T cell subsets in PBL from patients with MG is abnormal, compared with healthy control. After thymectomy, this abnormality could be revised. Fas expression on PBL of patients with MG is increased, which most likely reflects lymphocyte activation in vivo, as well as increased CD8 + T cell-mediated cytotoxic effect. Fas expression on PBL is decreased after thymectomy, which may be involved in the mechanism of thymectomy in MG therapy.