Uniprot Description A complex autoimmune disorder comprising two related diseases affecting the thyroid: Graves disease and Hashimoto thyroiditis. In both disorders, thyroid-reactive T-cells are formed and infiltrate the thyroid gland. In Graves disease, the majority of the T-cells undergo a Th2 differentiation and activate B-cells to produce antibodies against the TSH receptor, which stimulate the thyroid and cause clinical hyperthyroidism. In contrast, Hashimoto thyroiditis is characterized by Th1 switching of the thyroid-infiltrating T-cells, which induces apoptosis of thyroid follicular cells and clinical hypothyroidism.