Graves' hyperthyroidism following transient thyrotoxicosis during interferon therapy for chronic hepatitis type C.

We report a case of Graves' hyperthyroidism induced by long-term interferon (IFN) therapy. A 52-year-old woman suffered from chronic active hepatitis type C and was treated with a total of 456 x 10(6) units of IFN-alpha for 23 weeks. During the 12th week of treatment she showed transient thyrotoxicosis. One week after the termination of IFN therapy, TSH-receptor antibodies became positive and subsequently she showed Graves' hyperthyroidism. This case showed sequential manifestation from transient thyrotoxicosis to the appearance of TSH-receptor autoantibodies, and then the occurrence of Graves' hyperthyroidism during IFN therapy. The course of this case may be useful in the understanding of the pathogenesis of autoimmune hyperthyroidism.