Mukuta T, Yoshikawa N, Arreaza G, Resetkova E, Leushner J, Song Y H, Akasu F, Onaya T, Volpé R
Department of Medicine, Wellesley Hospital, University of Toronto, Ontario, Canada.
J Clin Endocrinol Metab. 1995 Apr;80(4):1264-72. doi: 10.1210/jcem.80.4.7714099.
We have postulated that a defect in specific antigenic induction of suppressor T lymphocytes may account for the immunoregulatory disorder in autoimmune thyroid disease. In this context, we have measured the proliferative responses of peripheral blood mononuclear cells (PBMC) to the synthetic peptides corresponding to the extracellular domain of the TSH receptor (TSHR) and recombinant glutamate decarboxylase (GAD65) by means of 3H thymidine incorporation. We have also studied the antigenic activation of CD4+ and CD8+ T lymphocytes by measuring human leukocyte antigen-DR (HLA-DR) expression on the cell surface by flow cytometric analysis. PBMC obtained from 47 patients with Graves' disease (GD) [including 19 hyperthyroid GD (hyper GD)], 18 with Hashimoto's thyroiditis (HT), 7 with nontoxic nodular goiter (NG), 18 with insulin-dependent diabetes (IDDM), and 20 normal controls (N), were cultured for 7 days in the presence or absence of the pool peptides representing 3 different segments of TSHR or GAD65 at final concentration of 30 micrograms/mL or 10 micrograms/mL. The proportion of subjects whose PBMC gave a positive proliferative response with a stimulation index (SI) of over 2.3 (i.e. above the mean +2 SD for N) to TSHR peptides was significantly higher in the hyper GD group than among euthyroid GD (eu GD), HT, IDDM, and N group. The corresponding differences in mean SI provided analogous results, showing significant responses above normal in only hyper GD. The CD4+ T lymphocytes from hyper GD group were significantly more activated by TSHR peptides compared to eu GD, HT, IDDM, and N, and this induction correlated to their thyroid hormone levels. Quite differently, the activation of CD8+ T lymphocytes from both hyper GD and eu GD group in response to TSHR peptides was impaired compared to HT, IDDM, and the N group; in contrast to the findings with CD4+ T lymphocytes, this was independent of thyroid hormone levels. On the other hand, while the CD8+ T lymphocytes from GD and N groups were activated equally by GAD65, the activation of CD8+ T lymphocytes from the IDDM group by GAD65 was impaired compared to the GD and N groups. In conclusion, the activation of CD8+ T lymphocytes from GD and IDDM by relevant antigens (i.e. TSHR peptides for GD and GAD65 for IDDM) was impaired, but not by irrelevant antigens (i.e. GAD65 for GD and TSHR peptides for IDDM). There was also a modest stimulation of CD8+ T cells from all groups by tetanus toxoid and cardiac myosin light chain peptide, both irrelevant antigens.(ABSTRACT TRUNCATED AT 400 WORDS)
我们推测，抑制性T淋巴细胞的特异性抗原诱导缺陷可能是自身免疫性甲状腺疾病免疫调节紊乱的原因。在此背景下，我们通过³H胸腺嘧啶核苷掺入法测定了外周血单个核细胞（PBMC）对与促甲状腺激素受体（TSHR）细胞外结构域及重组谷氨酸脱羧酶（GAD65）相对应的合成肽的增殖反应。我们还通过流式细胞术分析测量细胞表面人类白细胞抗原-DR（HLA-DR）的表达，研究了CD4⁺和CD8⁺T淋巴细胞的抗原激活情况。从47例格雷夫斯病（GD）患者[包括19例甲状腺功能亢进的GD（甲亢性GD）]、18例桥本甲状腺炎（HT）患者、7例非毒性结节性甲状腺肿（NG）患者、18例胰岛素依赖型糖尿病（IDDM）患者及20例正常对照（N）获取的PBMC，在存在或不存在代表TSHR或GAD65三个不同区段的混合肽的情况下培养7天，混合肽的终浓度为30微克/毫升或10微克/毫升。甲亢性GD组中PBMC对TSHR肽产生增殖反应且刺激指数（SI）超过2.3（即高于正常对照平均值+2标准差）的受试者比例显著高于甲状腺功能正常的GD（甲功正常GD）组、HT组、IDDM组及正常对照组。平均SI的相应差异得出类似结果，仅甲亢性GD组显示出高于正常的显著反应。与甲功正常GD组、HT组、IDDM组及正常对照组相比，甲亢性GD组的CD4⁺T淋巴细胞被TSHR肽激活得更显著，且这种诱导与它们的甲状腺激素水平相关。截然不同的是，与HT组、IDDM组及正常对照组相比，甲亢性GD组和甲功正常GD组的CD8⁺T淋巴细胞对TSHR肽的反应激活受损；与CD4⁺T淋巴细胞的结果相反，这与甲状腺激素水平无关。另一方面，虽然GD组和正常对照组的CD8⁺T淋巴细胞被GAD65同等激活，但与GD组和正常对照组相比，IDDM组的CD8⁺T淋巴细胞被GAD65的激活受损。总之，GD组和IDDM组的CD8⁺T淋巴细胞被相关抗原（即GD组的TSHR肽和IDDM组的GAD65）激活受损，但不被无关抗原（即GD组的GAD65和IDDM组的TSHR肽）激活。破伤风类毒素和心肌肌球蛋白轻链肽这两种无关抗原也对所有组的CD8⁺T细胞有适度刺激。（摘要截于400字）
