Complement-independent antithyroid cytotoxicity of sera of patients with autoimmune thyroid diseases

Abstract

The primary cultures of thyrocytes isolated from the paranodal tissue of euthyroid nodal goiter indicated that the sera from patients with Hashimoto ’s thyroiditis and Graves’ disease had complement-independent cytotoxicity. This effect was found in about 40% of the sera from patients at different stages of drug compensation of autoimmune thyroid diseases. The cytotoxic effect of the sera was not shown in the primary cultures of human skin fibroblasts. The detection rate of complement-independent cytotoxicity in the sera from patients with Hashimoto ’s thyroiditis and Graves’ disease coincided with that of elevated levels of soluble FAS-receptor ligand in the respective sera. Thyrocytes isolated from patients with Graves’ disease turned out to be resistant to the action of 60% of the cytotoxic sera. This resistance may be associated with the lowered FAS-receptor expression on these cells, which has been revealed in special studies.