The nature of enhanced natural killer lymphocyte cytotoxicity during anesthesia and surgery in patients with benign disease and cancer.

This study was instituted to determine the mechanism of enhanced natural killer (NK) lymphocyte activity during surgery. Natural cytotoxicity of whole blood to K562 target cells was assayed before anesthesia and during anesthesia and surgery in patients with benign and malignant gastrointestinal disease. Those patients with benign conditions and localized primary tumors showed enhanced NK lymphocyte cytotoxicity during surgery (p less than 0.025 and p less than 0.0025, respectively) but not patients with disseminated tumors. In patients with localized tumors, enhancement of NK lymphocyte cytotoxicity was an interferon-independent phenomenon but appeared to be related to a significant rise in the percentage of cells bearing the Leu 7 monoclonal antibody marker for NK cells (p less than 0.02). Exogenous leukocyte interferon caused further enhancement of NK cytotoxicity in patients with benign disease and some cancer patients. Enhancement of NK lymphocyte activity during surgery may be of significance in reducing tumor metastases by stimulation of natural cytotoxic mechanisms to circulating tumor emboli.