Thyroid Antibodies in Euthyroid Subjects after Iodine-131 Therapy

Abstract

established that irradiation of an organ can elicit an increase in the antibodies against this organ. The conditions for the formation of antibodies to cytoplasmic antigen are particularly favorable in hyperthyroidism, for the thyroid gland is then rich in such antigen and circulating antibodies are often present even in the case of the untreated disease. A general immunological hyperactivity has, moreover, been observed in the thyroxine-fed guinea pig (4). The investigation reported below was performed to examine whether, in the absence of hyperthyroidism, there is any increase in the thyroid auto-antibodies after radioiodine therapy. In earlier studies on hyperthyroidism, an increase in the antibodies to thyroid epithelial cytoplasm was found 2 to 12 months after radioiodine therapy (3). We have now studied in euthyroid subjects also the situation during the first 2 months after treatment. To examine the possibility of nonspecific serological reactions at low titers, the same tests for thyroid antibodies were performed after intensive irradiation of other organs than the thyroid gland. MATERIAL