Thyroid Autoimmunity Induced by Interferon Therapy

We have previously reported [1] that patients with carcinoid tumors on long-term therapy with human leukocyte-derived (huLe) interferon (IFN) may develop signs of thyroid autoimmunity: among 49 patients hyperthyroidism occurred in two and hypothyroidism in five. Antibodies against thyroid microsomal antigen and/or thyroglobulin were found in 13 patients, and in 7 of these the antibodies appeared after the start of therapy. In the present report, we have extended these observations in a larger patient series and include data on patients given long-term treatment with recombinant (r) IFNα. Moreover, the occurrence of simple epithelial cell autoantibodies, frequently seen in carcinoid patients receiving huLe-IFNα [2], and the correlation of these autoantibodies to thyroid dysfunction and/or thyroid-specific antibodies, was examined in sera from patients given huLe-IFNα or r-IFNα.