甲状腺球蛋白抗体IgG亚型在桥本甲状腺炎中的分布及意义

Distribution and significance of IgG subclasses of serum antithyroglobulin antibody in Hashimoto thyroiditis

目的探讨血清甲状腺球蛋白抗体（TgAb）IgG亚型在桥本甲状腺炎中的分布及意义。方法收集112例TgAb滴度升高的桥本甲状腺炎患者的血清，按甲状腺功能分为甲状腺功能减低（甲减）组、亚临床甲状腺功能减低（亚甲减）组和甲状腺功能正常组（功能正常组）。采用抗原特异性ELISA方法检测TgAb各IgG亚型阳性率及其滴度。结果TgAb各IgG亚型阳性率分别为IgG190．2％、IgG258．0％、IgG319．6％、IgG487．5％。甲减组及亚甲减组IgG1亚型滴度的几何均数均高于功能正常组（分别为1：450．8，1：245．5，1：8．7，P〈0．01）；甲减组与亚甲减组IgG2亚型滴度的几何均数均高于功能正常组（1：37．3，1：3．2，1：0．2，分别为P〈0．01和P〈0．05），并且甲减组IgG2亚型滴度的几何均数高于亚甲减组（P〈0．05）。结论桥本甲状腺炎TgAb亚型主要由IgG1、IgG2、IgG4组成。高滴度IgG1、IgG2可能与甲状腺功能损伤有关。

Objective To evaluate the distribution and significance of IgG subclasses of antithyroglobulin antibody in sera from patients with Hashimoto thyroiditis. Methods Sera from 112 patients with Hashimoto thyroiditis were collected and patients were divided into 3 groups, i. e. hypothyroidism, subclinical hypothyroidism and euthyroidism. Antigen specific ELISA was used to detect the distribution of IgG subclasses of antithyroglobulin antibody. Results The positive rates of IgG subclasses of TgAb were IgG1 90.2%, IgG2 58.0%, IgG3 19. 6% and IgG4 87.5% respectively. The mean geometric titers of IgG1 in sera from patients with hypothyroidism and subclinical hypothyroidism were 1 ： 450. 8 and 1 ： 245.5 respectively, both being significantly higher than that with euthyroidism （ 1： 8.7, P 〈 0. 01 ）. The mean geometric titers of IgG2 in sera from patients with hypothyroidism and subclinical hypothyroidism were 1 ： 37. 3 and 1 ： 3.2 respectively, both being also significantly higher than that with euthyroidism （ 1 ： 0. 2, P 〈0. 01 and P 〈 0. 05 respectively） and that with hypothyroidism was significantly higher than that with subclinical hypothyroidism （ P 〈 0. 05）. Conclusion The distribution of IgG subclasses of antithyroglobulin antibody in sera from patients with Hashimoto thyroiditis was predominantly IgG1, IgG2 and IgG4. High titers of IgG1 and IgG2 implicated the possibility of development from subclinical hypothyroidism to overt hypothyroidism.