CD4^＋ CD25^＋调节性T细胞与自身免疫性甲状腺疾病

CD4^＋ CD25^＋ regulatory T cell and autoimmune thyroid diseases

CD4^＋ CD25^＋调节性T细胞为新近发现的一群功能成熟的T细胞亚群。其特征性表达又头盒蛋白3（Foxp3）分子，专职免疫无能和免疫抑制，在维持外周免疫耐受，防止自身免疫性疾病发病中起着极为关键的作用？CD4^＋ CD25^＋调节性T细胞存A身免疫性甲状腺疾病（AITD）发病中的作用引起了人们的关注。动物实验发现CD4^＋ CD25^＋调节性T细胞存在与否决定了实验动物是否发生实验性自身免疫性甲状腺炎（EAT）和Graves病。人体研究发现CD4^＋ CD25^＋调节性T细胞数目和功能异常与人AITD发生密切相关。这些研究结果提示，CD4^＋ CD25^＋调节性T细胞可能在AITD发病中起重要作用。

CD4^＋ CD25^＋ regulatory T cells, which are important subsets of naturally occurring mature T ceils ,play important roles in the maintenance of immune tolerance and homeostasis. They exert anergy and suppression of immune by directly contracting with cells or secreting cytokines. Transcriptional factor Foxp3 is the most essential and special marker of the development and maintenance of them. The development of experimental autoimmune thyroiditis or Graves＇ disease in animals depends on the existence of CD4^＋ CD25^＋ regulatory T cells. Abnormal number and function of CD4^＋ CD25^＋ regulatory T cells exists in patients with autoimmune thyroid diseases. Studies suggested that CD4^＋ CD25^＋ regulatory T cells may play important roles in pathogenesis of autoimmune thyroid diseases.