Regulation of major histocompatibility complex gene expression in thyroid epithelial cells by methimazole and phenylmethimazole.

Increased expression of major histocompatibility complex (MHC) class-I genes and aberrant expression of MHC class-II genes in thyroid epithelial cells (TECs) are associated with autoimmune thyroid diseases. Previous studies have shown that methimazole (MMI) reduces MHC class-I expression and inhibits interferon-gamma (IFN-gamma or IFNG as listed in the MGI Database)-induced expression of the MHC class-II genes in TECs. The action of MMI on the MHC class-I genes is transcriptional, but its mechanism has not been investigated previously.