Long-term treatment with interferon-beta therapy for multiple sclerosis and occurrence of Graves' disease.

Interferon (IFN)-beta has become a widespread therapy for multiple sclerosis. As already reported for IFN-alpha, thyroid autoimmunity and dysfunctions have been observed also in course of IFN-beta therapy. Nevertheless, very few cases of Graves' disease, occurred in such condition, have been reported in literature. We here describe the case of a 40-year-old female affected by multiple sclerosis, who received IFN-beta-1b, 8 million IU s.c. every other day for her condition. After 22 months of cytokine administration, she developed a severe Graves' disease with persistently positive TR-Ab which suggested the withdrawal of the treatment. Our patient had performed a complete thyroid evaluation with normal findings, before and during the first 6 months of therapy. This case suggests that patients undergoing long-term IFN-beta therapy should be monitored for thyroid hormones and antibodies throughout the treatment as thyroidal side effect can be a late event.