Development of overt autoimmune hyperthyroidism in a patient therapeutically immunosuppressed after liver transplantation

Immunosuppression is a therapeutic maneuver directed at preventing transplant rejection. When applied to autoimmunity, immunosuppression is intended to target similar immune processes. We report an unusual case of a 35-year-old woman who developed autoimmune hyperthyroidism of Graves' disease while on immunosuppressive therapy for liver transplantation. Signs and symptoms of hyperthyroidism were already present when, misled by the concomitant toxic hepatic syndrome, liver rejection was first suspect-ed. Despite a therapeutic level of cyclosporine, elevated serum alanine and aspartate aminotransferase levels were noted. Consequently, a liver biopsy was performed to exclude an acute rejection. The findings were consistent with acute hepatitis without evidence of rejection. Then, the diagnosis of Graves' hyperthyroidism was considered and finally confirmed by finding a suppressed thyroid-stimulating hormone, elevated thyroid hormone levels, and a high and homogeneous thyroid uptake from radioactive iodine scan. Thyroid peroxidase antibody and thyroid-stimulating immunoglobulin were markedly elevated. The patient was treated with radioactive iodine, which resulted in improvement of symptoms and resolution of abnormal liver function tests. Although the mechanisms involved in transplant rejection and human autoimmunity are thought to be similar, the development of Graves' disease in this patient despite therapeutic immunosuppression suggests that the immunological processes may be different.