Abstract
To better understand the genesis of autoimmunity in Graves' disease (GD), it is essential to study the mechanism of apoptosis and cell proliferation in thyroid cells and intrathyroidal lymphocytic infiltrate of GD patients. Methods. A cross sectional, observational study performed by evaluating histopathological samples of thyroidectomy products from GD patients using immunohistochemistry. New histological sections were prepared for immunohistochemical analysis with markers of cell proliferation, antiproliferation, apoptosis, and antiapoptosis. Results. Patients with GD who underwent radioiodine therapy (RIT) had a lower lymphocytic expression level of p27Kip1, and those who took beta-blockers had higher expression levels of BID (BH3-interacting domain) and a lower Ki-67 expression level in thyrocytes than those who did not. The association of a shorter diagnostic time with a lower expression level of MCL-1 in thyroid cells suggests that the hyperthyroid state was related to a lower antiapoptotic effect on thyrocytes. In comparison to patients with GD not using antithyroid drugs (ATD), we found a lower expression level of BID in lymphocytes for those who used ATD. Conclusion. In GD, the hyperthyroid state was associated with a lower antiapoptotic effect on thyroid cells. RIT, beta-blockers, and thionamide act by stimulating apoptosis of thyrocytes by intrathyroidal lymphocytes.