The Role Of Regulatory T Cells And TGF-β₁in Autoimmune Thyroid Diseases

Objective The aim of this study is to investigate the roles of circulating CD4+CD25+regulatory T cells (Tregs), Foxp3and TGF-β1in the pathogenesis of autoimmune thyroid diseases (AITD), accordingly, it may clarify the immune pathogenesis of AITD and provide valuable experimental evidence to look for new immunotherapy methods. Methods30patients of Graves disease (GD) and20Hashimotos thyroiditis (HT) were enrolled, with the samples of20healthy control subjects. It is not statistically significant that the difference of age and sex in each group. To collect the peripheral blood prepares of patients with AITD before treatment, and have no other diseases. The proportion of circulating CD4+T cell and CD4+CD25+Tregs was assessed by flow cytometry. To get out total RNA, use RT-PCR and agarose gel electrophoresis techniques to semiquantitatively analyze Foxp3mRNA expression. ELISA to test the level of TGF-β1. The serum levels of thyroid hormone, thyroglobulin antibody (TGAb), thyroid peroxidase antibody (TPOAb), and thyrotrophin receptor antibody (TRAb) were measured with commercial electrochemiluminescence(ECL) Kits. Use t-test and pearson linear correlation to analysis the results with statistical software SPSS13.0. A P value of less than0.05was considered to indicate significance. Results The percentage of CD4+T cells in PBMC in GD group and HT group were (40.74±8.08)%,(35.59±7.93)%respectively, compared with the control group (38.12±7.29)%, there was no significance (P>0.05); the percentage of CD4+CD25+Tregs in CD4+T cells were (15.94±5.02)%,(14.42±3.06)%respectively, compared with the control group (23.23±4.72)%, there were significantly decreased proportion (P<0.05). The expression of Foxp3mRNA decreased obviously in Peripheral blood in GD group (0.17±0.05) and HT group (0.14±0.05), compared with the control group (0.27±0.06)(P<0.05). Compared with normal controls (88.71±14.69) ng/L, the expression of serum TGF-β1were higher in GD group (138.71±27.21) ng/L and HT group (112.47±22.16) ng/L (P<0.05). The level of TGF-β1in AITD patients had no correlation with Tregs and Foxp3mRNA(P>0.05); The level of Foxp3mRNA in AITD patients had positive correlation with Tregs(r=0.862, P<0.01). Conclusion The low expression of regulatory T cells and Foxp3mRNA in AITD Patients maybe involved in Pathophysiology of AITD, the expression of serum TGF-β1were increased in patients with AITD, there were no significant correlation with Tregs and Foxp3mRNA.