There is suggestive evidence of molecular mimicry that comes from thyroid cell expression of HLA class II molecules in patients with autoimmune thyroid disease (Graves' disease) that are not expressed in normal thyroid tissue, where MHC (HLA-DR) expression is theorized to be a direct result of viral infection or induced by T-cell cytokines (IFN-gamma and IFN-alpha) [10, 11]. This evidence concerns the gene IFNG and Graves disease.