Abstract: Objective To explore the role of regulatory T-lymphocytes(Treg) in the immune pathogenesis of subacute thyroiditis(SAT). Methods The proportion of Treg in CD4+T cells in peripheral blood of 46 SAT patients and 15 controls was detected using flow cytometry. And the concentration of interleukin-10(IL-10), transforming growth factor-beta1(TGF-β1) and prostaglandin E2(PGE2) in serum of 46 SAT patients and 15 controls was measured with ELISA. In addition, the Forkhead box protein 3(Foxp3) positive cells in thyroid tissue of 29 SAT patients and 20 controls was detected by immunohistochemistry. Results The proportion of Treg in peripheral blood of SAT patients was significantly lower than that of controls (P<0.05). And the concentration of TGF-β1 in serum of SAT patients was apparently higher than that of controls(P<0.05). Additionally, the positive rate of Foxp3 in thyroid tissue of SAT patients was markedly higher than that of controls(P<0.05). Conclusions The decrease of Treg may play an important role in the immune pathogenesis of SAT.

Key words: subacute thyroiditis, regulatory T-lymphocytes(Treg), interleukin-10(IL-10), transforming growth factor-beta1(TGF-β1), prostaglandin E2(