HLA-DP, DQ and DR gene expression in Graves' disease and normal thyroid epithelium

HLA class II antigen expression by human thyroid epithelium may influence the pathogenesis of autoimmune thyroid disease. HLA-DP, DQ and DR alpha chain-specific RNA probes and monoclonal antibodies specific for the three HLA-D subregion products were used to analyze class II antigen expression in thyroid epithelial cells from normal thyroid tissue and thyroid tissue obtained from patients with Graves' autoimmune thyroid disease. Class II alpha chain RNA transcripts, as well as immunoreactive protein representing all three HLA class II antigens, were detected in Graves' thyroid tissue, and the levels of class II antigen expression appeared to correlate with the degree of lymphocytic infiltration within the gland. Thyroid epithelial cells from normal thyroid glands contained low or absent levels of HLA class II alpha chain mRNA and contained no detectable immunoreactive HLA class II antigen. Thyroid cell monolayer cultures prepared from both Graves' disease and normal thyroid glands exhibited coordinate induction by lectin or human recombinant gamma interferon of HLA-DP, DQ and DR gene expression. These data demonstrate the potential for HLA-DP, DQ and DR antigen expression in thyroid epithelium, and imply a dose relationship between lymphocytic infiltration and coordinate transcription and translation of HLA class II genes.