Inhibition of effector cell function in human antibody-dependent cellular cytotoxicity by sera from cancer patients

The effect of sera from 256 human cancer patients on the human antibody-dependent cellular cytotoxicity (ADCC) assay was studied. The cancer sera were compared to normal sera for their ability to alter the effector function of lymphocytes following 30 minutes' treatment at 37 degrees C. Even with this brief treatment, 74% of the 256 cancer sera inhibited effector activity. In most instances this inhibition was greater in patients with metastatic disease than in those without. Patients with colon and prostate cancer showed a statistically significant increase in inhibition among patients with disseminated disease (P less than 0.02 and P less than 0.01, respectively). An opposite effect was noted only in melanomas. It is suggested that the inhibition of the effector function in ADCC is a potential in vitro measure of the immunologic status of cancer patients.