CD26/DPP4 Levels in Peripheral Blood and T Cells in Hashimoto's Thyroiditis with Normal Thyroid Function

Aims: Exploring the CD26 expression in peripheral blood and T cells in Hashimoto's thyroiditis with normal thyroid function. And evaluating the association between CD26 expression and TGAb and TPOAb levels. Methods: We collected peripheral blood and thyroid tissues from healthy controls and HT patients. Then we measured circulating CD26 level via ELISA and membrane-bound CD26 on Th and Tc cells via flow cytometry. Immunochemistry is used to evaluate CD26 expression in thyroid tissue. Moreover, we analyzed the correlation between serum CD26 and autoantibodies and CD26 on T cells. Results: Compared with healthy controls, CD26 expression in serum and thyroid tissues were obviously lower in HT patients with normal thyroid function. And serum CD26 level was negatively related with TGAb. While no correlation was seen between membrane-bound CD26 and autoantibodies. There was no relation between serum CD26 and CD26 expression on T cells. Conclusions: Taken together, our results show that the level of serum CD26 was associated with TGAb in HT patients with normal thyroid function.