Experimental thyroiditis in the rhesus monkey. 3. Course of the disease

Abstract

Two rhesus monkeys were injected with monkey thyroid extract plus complete Freund adjuvant, and the immunopathological changes were followed for over a year.

In one monkey the level of antibody to thyroglobulin, as measured by tanned cell haemagglutination, increased gradually over the period. Antibodies to constituents of the thyroid epithelial cells themselves were demonstrated by complement fixation and cytotoxic reactions. These titres were greatest between 80 and 150 days and then diminished. Skin test reactions of delayed hypersensitivity were present at the same time. As followed by repeated biopsies, the pathological changes progressed during the course of the disease from moderate infiltration to virtual replacement of all the thyroidal elements by fibrosis.

The second monkey produced the highest titre of tanned cell haemagglutinating antibody early in immunization, followed by gradual decrease. Complement-fixing antibodies were present primarily between days 150 and 200, and then disappeared. Cytotoxic antibodies were insignificant in the samples tested and only minimal skin reactions were elicited. The first biopsy taken after 100 days showed severe thyroiditis. Subsequent examinations revealed regression and regeneration so that 18 months after initiation of the experiment, the thyroid gland was nearly normal in appearance.