Graves病甲状腺共刺激分子GL50-ICOS的表达及其免疫病理意义

Co-stimulatory signal GL50-ICOS expression in thyroid of Graves＇ disease and its immune pathogenetic significance

目的 研究共刺激分子GL50-ICOS在Graves病（GD）甲状腺组织中的表达及其免疫病理意义.方法运用细胞培养、流式细胞术、RT-PCR、Western印迹和免疫组化技术,检测GD甲状腺组织和原代培养的甲状腺滤泡细胞（TFC）共刺激分子GL50和ICOS的表达.结果 （1）与正常同龄对照相比,CD4＋CD28-T细胞群体在GD患者外周血中显著升高,其表面ICOS表达上调.（2）RT-PCR显示,GD患者甲状腺组织中有ICOS mRNA表达,与对照非毒性甲状腺肿（NTG）组相比具有统计学差异（P＜0.01）.（3）Western印迹显示,GL50蛋白在10例GD患者组织中全部表达,较对照组差异有统计学意义（P＜0.01）.（4）与对照甲状腺腺瘤组相比,GL50在20例GD患者组织切片中全部检出,而对照组无阳性表达（P＜0.01）.（5）炎性细胞因子刺激体外原代培养的甲状腺滤泡细胞表面上调表达GL50（P＜0.05）.结论共刺激分子GL50-ICOS在Graves病甲状腺组织异常表达.

Objective To study the expression of co-stimulatory molecules, GL50-ICOS, in thyroid tissue of patients with Graves＇ disease （GD） and to explore their relationship with the immune pathogenesis of GD.Methods RT-PCR, Western blot, immunohistochemistry were applied to detect the expression of GL50-ICOS in thyroid of GD. Thyrocytes were cultured in the absence or presence of pro-inflammatory cytokines. The expression of GL50 on thyroid follicular cells （TFC） was further measured by flow cytometry. Results （1） In GD patients,the percentage of CD4＋ CD28- T cells was significantly increased as compared with the control healthy individuals. The expression of co-stimulatory molecule ICOS was up-regulated. （2） The mRNA level of ICOS was significantly increased in GD patients than that in nontoxic goiter（NTG） patients（P〈0.01）. （3）Compared with NTG control group, the GL50 protein expression was much higher in thyroid tissues of GD patients （P 〈0.01）. （4）The results of immunohistochemistry showed that GL50 expression was observed in all GD thyroid tissues, while no expression of GL50 was detected in NTG thyroid tissues（P〈0. 01）. （5） The expression of GL50on primary cultured thyroid follicular cells was significantly increased under the stimulatation of pro-inflammatory cytokines in vitro. Conclusion GL50-ICOS is expressed abnormally in thyroid tissue of patients with GD.