Long term spectrotypic and idiotypic stability of thyroglobulin autoantibodies in patients with Hashimoto's thyroiditis.

Isoelectric focusing of serial bleeds from patients with Hashimoto's thyroiditis was carried out and thyroglobulin (Tg) autoantibodies visualized using 125I-labelled Tg followed by autoradiography. Although the spectrotype of these antibodies was polyclonal and varied from patient to patient, each individual's spectrotype remained constant during the disease. Similar results were obtained if immunoblots were stained with rabbit anti-idiotype (anti-Id) raised to these autoantibodies. Using radioimmunoassay (RIA), it is shown that the levels of Id remain constant over several years whether assayed on crude immunoglobulin (Ig) fractions or affinity-purified anti-Tg. Therefore, once established, the autoimmune disease appears to be stable in terms of autoantibody spectrotype and idiotype in the patients studied.