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

Immunosuppression is a therapeutic maneuver directed at preventing transpla nt rejection. When applied to autoimmunity, immunosuppression is intended t o target similar immune processes. We report an unusual case of a 35-year-o ld 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 tox ic hepatic syndrome, liver rejection was first suspect-ed. Despite a therap eutic level of cyclosporine, elevated serum alanine and aspartate aminotran sferase levels were noted. Consequently, a liver biopsy was performed to ex clude an acute rejection. The findings were consistent with acute hepatitis without evidence of rejection. Then, the diagnosis of Graves' hyperthyroid ism was considered and finally confirmed by finding a suppressed thyroid-st imulating hormone, elevated thyroid hormone levels, and a high and homogene ous thyroid uptake from radioactive iodine scan. Thyroid peroxidase antibod y and thyroid-stimulating immunoglobulin were markedly elevated. The patien t was treated with radioactive iodine, which resulted in improvement of sym ptoms and resolution of abnormal liver function tests. Although the mechani sms involved in transplant rejection and human autoimmunity are thought to be similar, the development of Graves' disease in this patient despite ther apeutic immunosuppression suggests that the immunological processes may be different.