Primary hypothyroidism associated with interleukin-2 and interferon alpha-2 therapy of melanoma and renal carcinoma.

Four patients out of twenty with renal cancer and melanoma undergoing cancer immunotherapy with interleukin 2 (IL-2) and interferon alpha-2 (IFN-alpha 2) had laboratory evidence of hypothyroidism starting at cycle three to six, with a decline in serum thyroxine below normal and, in three cases, a rise in serum thyrotropin and thyroglobulin. One hypothyroid patient had elevated serum antimicrosomal antibody titres before the start of treatment and two others responded similarly during therapy. Three of the sixteen euthyroid patients also developed elevated titres of this antibody.