T cell-derived leptin contributes to increased frequency of T helper type 17 cells in female patients with Hashimoto’s thyroiditis

Abstract

Leptin modulates T cell function and plays an important role in autoim- mune diseases. Our study aimed to explore the role of leptin and T helper type 17 (Th17) cells in Hashimoto’s thyroiditis patients. Twenty-seven patients with Hashimoto’s thyroiditis (HT) and 20 healthy controls were enrolled into the current study. A modest increase of plasma leptin in HT patients and the CD4+ T cell-derived leptin from HT patients was stronger than that from healthy controls. In HT patients, there are no statistically sig- nificant correlations between plasma leptin concentrations and the percent- age of Th17 cells or the level of retinoic acid-related orphan receptor gt (RORgt), but strong positive correlations were observed between CD4+ T cell-derived leptin and the percentage of Th17 cells or the level of RORgt mRNA, and additionally significantly up-regulated leptin, interleukin (IL)17 and RORgt mRNA levels in the thyroid tissue. Furthermore, neutralization of leptin decreases the frequency of Th17 cells in vitro. Current study has revealed an increased leptin involvment in Hashimoto’s thyroiditis associ- ated with an increased number of Th17 cells.