Immunopathological Studies of Chronic Thyroiditis : Part 1. Chemical and Immunopathological Studies on Thyroid Supernatant

Abstract

The soluble fraction of centrifugally fractionated thyroid homogenates was studied by paper electrophoresis, ultracentrifugation, column chromatography and immunologic techniques in diseased human thyroid glands. In all the chemical separations of the thyroid supernatant fraction, thyralbumin and thyroglobulin were always demonstrated. In the paper electrophoresis, the mean percent ratio. of thyralbumin was 24.7±11.4% in chronic thyroiditis, 10.7±11.4% in hyperthyroidism, 48.0±15.6% in thyroid cancer, 46.4±11.5% in adenoma part of thyroid adenoma and 13.5±4.4% in normal part in thyroid adenoma. The amount of thyralbumin varied markedly, with a tendency towards an increase in chronic thyroiditis, adenoma part of thyroid adenoma and thyroid cancer, and a decrease in hyperthyroidism and normal part in thyroid adenoma. Thyroglobulin and thyralbumin were evaluated serologically, using anti-human serum albumin and Hashimoto serum. In double diffusion gel precipitation tests, thyroglobulin produced a line with Hashimoto serum and thyralbumin crossreacted with antiserum to human serum albumin. Intradermal tests, using thyroglobulin and thyralbumin as antigen, were carried out in 6 patients with chronic thyroiditis and 3 normal subjects. There was observed close correlation between the presence of circulatory thyroid precipitins and strongly positive skin reactions, with thyroglobulin as antigen, but intradermal tests with thyralbumin as antigen were all negative. These findings show that thyroglobulin is antigenic in thyroiditis but not thyralbumin. The histologic localization of thyroglobulin and thyralbumin by direct immunofluorescent staining was also studied in an attempt to demonstrate the existence of two independent thyroid proteins. The thyroglobulin was characterized by staining of thyroid colloid only, but thyralbumin was characterized by staining of thyroid colloid, cytoplasm of thyroid epithelium, and interstitial substances. These findings strongly suggest that normally thyroglobulin is contained wholly within the thyroid vesicles and is therefore "inaccessible" to antibody-producing tissues, but that thyralbumin exists within or outside the thyroid vesicles and "accessible".