Clinical significance of natural killer activity in patients with transitional cell carcinoma of the bladder.

We studied the relationship of natural killer activity from peripheral blood mononuclear cells with clinical stage of disease and the different modalities of treatment in 67 untreated patients with transitional cell carcinoma of the bladder and 29 normal controls. Peripheral blood mononuclear cells from 39 patients with superficial bladder tumor (stages Ta and T1) showed a natural killer cell activity similar to that of controls (p greater than 0.05), while in 28 patients with infiltrating tumors (stages T2, T3 and T4) this activity was significantly depressed (p less than 0.