Preliminary Study On The Immune Mechanism Of Treg In Subacute Thyroiditis

Objective: To preliminarily study the role of the regulatory T cells(Treg)in the immune pathogenesis of subacute thyroiditis(SAT)and its possible mechanism,we detected the proportion of Treg and the concentration of related cytokines in peripheral blood,and the expression and distribution of forkhead protein 3(Foxp3)in thyroid tissue of patients with SAT.Methods: 46 patients with SAT and 15 normal controls were chosed,and the proportion of CD4+CD25+T cells and CD4+CD25+CD127-Treg cells in CD4+T cells in peripheral blood was detected by flow cytometry.And the concentration of interleukin-10(IL-10),transforming growth factor beta1(TGF-?1)and prostaglandin E2(PGE2)in serum was measured with ELISA.Meanwhile,thyroid function,erythrocyte sedimentation rate(ESR),C reactive protein(CRP)and other biochemical indices were also detected.Then the above indexes of SAT group and normal control group were compared,and the correlation of the observed indexes were also analysed.In addition,thyroid specimens of 29 SAT patients and 20 normal controls were selected.The expression of Foxp3 in thyroid tissue was detected by immunohistochemical method,and the results were compared between the two groups.Results: 1.General situation: Compared with the normal control group,the concentration of TT3,TT4,FT3,FT4 and CRP was increased,the concentration of TSH was decreased,and the rate of ESR was accelerated in SAT group,the differences were all statistically significant(P<0.05).2.The proportion of Treg cells in peripheral blood: The proportion of CD4+CD25+CD127-Treg cells in peripheral blood of SAT group was significantly lower than normal control group,and the differences were statistically significant(P<0.05).But the proportion of CD4+CD25+T cells and CD4+T cells in peripheral blood of SAT group had no statistically differences with normal control group(P>0.05).3.The concentration of cytokines in serum: The concentration of serum TGF-beta 1of SAT group was significantly higher than that of normal control group(P<0.05),and there were no significant differences between the two groups in the concentration of IL-10 and PGE2(P>0.05).4.The expression of Foxp3 protein in thyroid tissue: The positive rate of Foxp3 expression in thyroid tissue of SAT group was significantly higher than that of normal control group,and the differences were statistically significant(P<0.05).5.Correlation Analysis: In patients with SAT,the concentration of TGF-beta1 was not significantly correlated with TT3,TT4,TSH,ESR and CRP(P>0.05).And the proportion of Treg cells was not significantly correlated with TT3,TT4,FT3,FT4,TSH,ESR and CRP(P>0.05),but ESR was positively correlated with CRP(r=0.654,P<0.05).Conclusions: 1.The proportion of Treg cells in the peripheral blood of patients with SAT is decreased,whereas the expression of Foxp3 protein in local thyroid tissue is increased.The overall decline of Treg cells and the increased inflammatory injury of thyroid tissue may cause SAT.Increased infiltration of Treg cells in thyroid tissue may be the result of a protective regulatory effect.2.The differentiation and maturation of Treg cells are related to the pathogenesis of SAT,but not significantly related to the intensity of inflammation,clinical manifestations,thyroid function and other indicators of SAT.Therefore,the differentiation and maturation of Treg cells have nothing to do with the severity of the disease.