中文摘要：

目的：比较重症肌无力患者胸腺与正常胸腺中CD53与胸腺细胞亚群的差异,探讨重症肌无力患者胸腺异常增生的机制。方法：采用流式细胞术分析重症肌无力患者胸腺与正常胸腺（对照组）中胸腺细胞CD4、CD8、CD45RA、CD45RO的表达,采用实时荧光定量PCR技术检测重症肌无力患者和对照组胸腺组织CD53mRNA的表达水平。结果：重症肌无力患者胸腺双阳性细胞（CD4＋CD8＋）、单阳性细胞（CD4＋CD8-和CD4-CD8＋）均高于对照组差异有统计学意义（P〈0.01）。CD45RA分子表达明显低于对照组（P〈0.01）,CD45RO分子表达明显高于对照组（P〈0.01）。荧光定量PCR发现CD53mRNA的相对表达量在重症肌无力患者胸腺组织中为（4.45±0.5）,对照组为（5.58±3.140）,与对照组相比较,重症肌无力患者胸腺组织中CD53mRNA的表达上调2.66倍。结论：CD53与重症肌无力患者胸腺细胞亚群异常分布有关,可能与重症肌无力胸腺异常及其发病机制有关。

英文摘要：

Objective To explore the pathogenesis of hyperplasia in myasthenia gravis by comparing the differential expression of CD53 and thymocyte subgroups in thymus between myasthenia gravis patients and normal controls.Methods The expressions of CD4,CD8,CD45RA and CD45RO in thymus of myasthenia gravis patients and normal controls were detected with flow cytometry.The mRNA expression level of CD53 in thymus of myasthenia gravis patients and healthy controls was analyzed with real-time quantitative PCR.Results The double positive thymocytes（CD4＋CD8＋）in thymus of myasthenia gravis patients were significantly lower than those in normal controls（P0.01）,and the single positive thymocytes（CD4＋CD8-or CD4-CD8＋）in thymus of myasthenia gravis patients were significantly higher than those in normal controls（P0.01）.The expression of CD45RA in myasthenia gravis was significantly lower than normal controls,but the expression of CD45RO in myasthenia gravis was significantly higher than normal controls.Real-time PCR showed that the average quantity of CD53 mRNA in myasthenia gravis and normal control was 4.45±0.5 and 5.58±3.14,respectively.In comparison with normal controls,the expression of CD53 gene in myasthenia gravis had 2.66 fold up-regulation.Conclusion The higher expression of CD53 mRNA in the thymus of myasthenia gravis may be associated with the abnormal distribution of thymocytes subgroups,and it may be involved in the pathogenesis of hyperplasia in the thymus of myasthenia gravis.