Role of Follicular Helper and Follicular Regulatory T Cells in Hashimoto's Thyroiditis

Hashimoto thyroiditis, also known as chronic autoimmune thyroiditis and chronic lymphocytic thyroiditis, is an autoimmune disease in which thyroid cells are destroyed via cell and antibody-mediated immune processes. It is the most common cause of hypothyroidism in developed countries. In contrast, the most common cause of hypothyroidism worldwide is an inadequate dietary intake of iodine. The pathophysiology of Hashimoto thyroiditis involves the formation of antithyroid antibodies that attack the thyroid tissue, causing progressive fibrosis. The diagnosis can be challenging, and consequently, the condition is sometimes not diagnosed until late in the disease process. The most common laboratory findings demonstrate elevated thyroid-stimulating hormone (TSH) and low thyroxine (T4) levels, coupled with increased antithyroid peroxidase (anti-TPO) antibodies and antithyroglobulin (anti-Tg) antibodies .

Recent years have shown that Hashimoto thyroiditis development depends on an immune defect in an individual with genetic susceptibility together with environmental factors .