重症肌无力合并甲状腺功能亢进外周血T淋巴细胞Fas表达研究

Expression of fas antigen in peripheral blood T lymphocytes in patients with myasthenia gravis complicating with hyperthyroidism

目的探讨Fas介导的细胞凋亡与重症肌无力(MG)合并甲状腺功能亢进(甲亢)机制的关系。方法对2007年10月至2009年12月中山大学附属第五医院收治的17例MG患者及13名健康对照者进行研究,采用流式细胞技术检测外周血T淋巴细胞表面CD4、CD8及Fas的表达。结果合并甲亢的MG患者(5例)中眼肌型MG比例高于无合并甲亢MG组(40.0%对16.7%),胸腺增生及胸腺瘤的发生率均比无合并甲亢MG组低(前者20%对50%;后者0对25%),但差异无统计学意义。合并甲亢MG组患者外周血T淋巴细胞中CD4+CD8-细胞比例比对照组高(P=0.034)。合并甲亢MG组外周血T淋巴细胞中CD4+Fas+、CD4+CD8+Fas+细胞比例比对照组高,CD4+CD8+Fas+细胞比例比无合并甲亢MG组高,差异有统计学意义(均P<0.05)。结论甲亢在MG中发生率较高;合并甲亢的MG患者外周血CD4+T淋巴细胞中Fas的表达升高,可能与MG合并甲亢的发病机制有关。

Objective To investigate the correlation between Fas-mediated apoptosis and the pathogenesis of myasthenia gravis （MG） complicating with hyperthyoidism. Methods A total of 17 patients with MG and 13 normal controls were enrolled from The Fifth Affiliated Hospital of Sun Yat-sen University between October 2007 and December 2009. Expressions of cellular surface CD4, CD8 and Fas in peripheral blood T lymphocyte were analyzed via flow cytometry. Results Of 5 pa- tients with MG who had hyperthyroidism, prevalence of ocular MG was higher than those who had MG without hyperthyroidism （40.0% vs 16.7% ）,and by contrast, lower prevalence of thyroid hyperplasia and thymoma was associated with patients who had MG without hyperthyroidism （thyroid hyperplasia：20% vs 50% ;thymoma：0 vs 25 %, both P 〉 0.05 ）. Patients with MG complicating with hyperthyroidism yielded a higher proportion of peripheral blood CD4 ＋ CD8 - cells as compared with normal controls （ P = 0. 034 ）. Additionally, as compared with that of controls, a higher proportion of peripheral blood CD4 ^＋ Fas^＋ and CD4 ＋ CD8 ^＋ Fas^＋ cells was found in patients who had MG complicating with hyperthyroidism （ both P 〈 0. 05 ）. These patients were found to present higher proportion of peripheral CD4 ^＋ CD8 ^＋Fas^ ＋ than those who had MG without hyperthyroidism （ P 〈 0. 05 ）. Conclusion Higher prevalence of hyperthyroidism is associated in patients with MG. Up-regulated expression of Fas antigen in peripheral blood CD4^ ＋ T lymphocytes in patients who had MG complicating with hyperthyroidism may be correlated with the pathogenesis.