THE ROLE OF IODINE IN AUTOIMMUNE-THYROIDITIS

Like most cancers, autoimmune diseases generally are due to the intera ction of a number of genetic traits with an environmental trigger. Aut oimmune thyroiditis, a model of organ-specific autoimmune disease, is associated with iodine as a precipitating environmental factor. T cell s from patients with chronic thyroiditis proliferate in response to no rmal human thyroglobulin, but fail to react with non-iodinated thyrogl obulin. Using a selected monoclonal antibody, we were able to identify a binding site on thyroglobulin containing iodinated thyronine. The g reatest affinity was for tetraiodothyronine and binding depended upon the number as well as the positions of iodines. We have also studied a n inbred strain of mice, NOD-H2(h4), that developed thyroiditis sponta neously. The onset of disease was hastened in a dose-dependent manner by adding iodine to the drinking water. The occurrence of disease was greater in conventional than in specific pathogen-free mice and correl ated with T-cell proliferation and IgG(2b), antibody to thyroglobulin.