Chemokines modulate experimental autoimmune thyroiditis through attraction of autoreactive or regulatory T cells

A critical event in the pathogenesis of experimental autoimmune thyroiditis (EAT) is the entry of thyroid-specific T lymphocytes into the thyroid gland. To investigate the role of soluble mediators in that infiltration, we have assayed the expression of various chemokines in diseased thyroid glands and in cytokine-treated cultures of normal thyroid epithelial cells. MCP-1 (monocyte chemotactic protein-1) and RANTES are produced during EAT and induced in vitro by IFN-gamma, IL-10, TNF-alpha, and IL-1beta. In vitro chemotaxis experiments using immune lymph node (LN) cells showed that RANTES attracted mTg-specific responder LN cells, whereas MCP-1 attracted mTg-specific CD4(+), CD25(+) regulator cells that secreted IL-10. The in vivo transfer of LN T cells attracted in vitro either by RANTES or by MCP-1 confirmed their opposite effects on the course of EAT.