Natural killer cell activity in patients with urologic cancer

Cell-mediated cytotoxicity in patients with urologic cancer was studied using the K562 cell line as target cell by a 4-hour chromium-51 release assay. Lysis of target cells by mononuclear cells of a healthy subject, over an 8-hour incubation period, demonstrated a linear function of incubation time and effector:target ratio. Natural killer (NK) cell activity was found decreased (mean 30.6%) in peripheral blood lymphocytes from 42 untreated patients with urologic cancer when compared to 20 healthy subjects (63.6%) and to 10 patients with varicocele, stone disease and benign prostatic hypertrophy (58.1%; p less than 0.05). There was no correlation between NK cell activity and the grade or stage status in bladder cancer patients. No age-dependent changes in NK cell activity could be found between young and aged groups of healthy subjects. Healthy male subjects have higher levels of NK cell activity (77.7%) than healthy female subjects (49.5%). Postoperative NK activity rose in 5 out of 6 cancer patients. It indicates that tumors may have an inhibitory effect on the surveillance activity of NK cells.