Development of thyroid autoimmunity after administration of recombinant human interferon-alpha 2b for chronic viral hepatitis.

To investigate the frequency and clinical characteristics of autoantibody formation and development of autoimmune thyroid disease after interferon therapy, we measured the autoantibodies to thyrotropin receptor (TBII), thyroglobulin (ATA), and microsomal antigen (AMA) in 28 patients with histologically proven chronic viral hepatitis [25 males, three females; mean age 38.7 +/- 8.7 (SD) yr] receiving recombinant interferon-alpha 2b (IFN-alpha) treatment. Twenty patients with chronic hepatitis B (positive for HBsAg, HBeAg, and HBV DNA) and eight patients with chronic hepatitis C (positive for anti-HCV and HCV RNA) received IFN-alpha, 3 million units subcutaneously, three times a week for 6 months. Before, during, and up to 6 months after IFN-alpha therapy, thyroid hormone levels and titers of AMA, ATA, and TBII were measured every 2 months. None of them had thyroid dysfunction or antithyroid autoantibodies before IFN-alpha treatment. A 34-yr-old male patient developed Graves' disease during the last month of therapy. He required long-term antithyroid medications, even after discontinuation of IFN-alpha. Another 44-yr-old female patient developed AMA during IFN-alpha treatment; however, thyroid function remained normal and goiter did not develop in this patient. No other patient developed thyroid autoantibodies and thyroid dysfunction. In summary, only a small minority of patients will develop thyroid autoimmunity during IFN-alpha therapy, and much less often with this low dose of IFN-alpha.