Immunoglobulin and T cell antigen receptor gene arrangements indicate that the immune response in autoimmune thyroid disease is polyclonal.

To further define the degree of heterogeneity of the antibody and cellular immune responses in autoimmune thyroid disease, we used Southern blot hybridization techniques to analyze the arrangements of immunoglobulin and T cell antigen receptor genes in circulating lymphocytes and in those infiltrating the thyroid gland in nine patients with thyrotoxicosis due to Graves' disease and five patients with Hashimoto's thyroiditis. The sensitivity of these techniques was sufficient to detect a monoclonal population when there was as little as 1% clonal involvement in a mixed cell population. In the patients studied, DNA from non-T peripheral blood cells and non-T intrathyroid lymphocytes had only a germline gene pattern and no clonal nongermline rearrangements of immunoglobulin genes, as assessed using an immunoglobulin joining heavy chain (IgJH) gene probe. An analysis of the DNA from peripheral blood T cells or intrathyroidal lymphocytes revealed polyclonal gene rearrangement patterns and no clonal nongermline rearrangements of the T cell antigen receptor-beta and -gamma genes, as assessed using T constant-beta and T joining -gamma gene probes. These results indicate that the lymphocytes in peripheral blood and those infiltrating the thyroid gland in patients with autoimmune thyroid disease are of polyclonal origin.