[The role of Th17 cells and IL-17 in Hashimoto's thyroiditis: Review].

Patients with Hashimoto's thyroiditis had increased numbers of Th17 cells in serum and thyroid tissue, significantly elevated levels of interleukin 17 (IL-17), and an imbalance in the ratio of Th17 cells to regulatory T cells (Tregs). The reduced Tregs' ratio leads to a reduction in immunosuppressive function within the thyroid gland, while Th17 cells are involved in the development of HT by regulating the expression of pro-inflammatory cytokines in the thyroid gland and mediating thyroid tissue fibrosis through the secretion of IL-17.