Expression of the Extracellular Domain of the Thyrotropin Receptor Based on mRNA Isolated from Thyroid Tissue and Whole Blood of Patients with Toxic Diffuse Goiter (Graves' Disease).

Fragments of the thyrotropin receptor gene (TSHR) encoding 432- and 389-bp regions of the extracellular domain corresponding to the autoantibody binding sites in autoimmune diseases of the thyroid gland (Graves' disease and Hashimoto's thyroiditis, respectively) were cloned based on mRNA isolated not only from the thyroid tissue, but also from the whole blood of patients with toxic diffuse goiter (Graves' disease). In a group of 18 patients, the 432-bp fragment was detected in 6 patients and the 389-bp fragment was detected in 3 patients. In one patient, both fragments were isolated from the blood. The results indicate that TSHR is expressed in the blood in 30% of patients with Graves' disease.