Immunologic aspects of human thyroid cancer. Humoral and cell‐mediated immunity, and a trial of immunotherapy

Immunologic studies were performed on 16 patients with thyroid cancer. Circulating leukocyte counts increased, parallel to development of the terminal stage of disease, but total lymphocytes decreased. Serum immunoglobulin and complement were high, even though almost all patients showed negative antithyroid antibodies. Delayed skin hypersensitivity to bacterial and viral antigens and lymphocyte responsivity to PHA were not impaired at the initial stage of disease, but were impaired in terminal illness. Cell‐mediated immunity (CMI) to tumor antigens(s) was measured using the assays of lymphotoxin, migration inhibition factor, and peripheral leukocyte migration inhibition. A few patients showed significant response to tumor antigen, but not to homogenates of Graves' thyroid gland. Active immunotherapy was applied to three patients. Two patients, who were in the terminal stage of illness, could not develop generalized CMI; immunization did not alter the patients' rapid downhill course. One patient developed in vitro evidence of CMI against cancer tissue antigens, associated with decrease in tumor size. Four months after immunization, CMI was impaired in autologous plasma culture, but not in cultures in allogenic normal plasma.