Antibody inducing lymphocyte cytotoxicity (ADCC) and lymphocyte-mediated cytotoxicity in auto-immune thyroid diseases

Addition of heat-inactivated serum from patients with autoimmune thyroid diseases to normal nonadherent human lymphoid cells caused significant lysis of thyroglobulin or crude thyroid extract-coated erythrocytes. Serum from 9/10 patients with Hashimoto's thyroiditis induced significant chromium release by normal lymphocytes at higher dilution (greater than 1 : 1 000) than in other thyroid diseases, the mean highest positive dilution being 1 : 535 in Grave's disease and approximately 1 : 200 in primary hypothyroidism, hyperthyroidism without exophthalmos and non toxic goitres. Lymphocyte-mediated cytotoxicity in the absence of serum was found positive on one half of the patients with lymphocyte-dependent antibody. Besides an appraisal of autoimmunization in thyroid diseases, such cell-mediated reactions may indicate how the gland is damaged in autoimmune thyroid diseases.