Definition of Autoimmune thyroid disease

Autoimmune thyroid disease: Disease of the thyroid gland due to autoimmunity in which the patient's immune system attacks and damages their thyroid. Graves disease and Hashimoto thyroiditis are forms of autoimmune thyroid disease. In these diseases, thyroid-reactive T cells are formed that infiltrate the thyroid gland. Both disorders are common with a prevalence of about 1% in the US. See also: Graves' disease; Hashimoto's thyroiditis