[Changes in the activity of natural killer cells in superficial bladder cancer during intravesical BCG therapy]

Alteration of natural killer (NK) activity from the peripherial blood was examined in the patients with superficial bladder cancer during two years between 1989-1991. The natural killer cell activity in patients with superficial bladder cancer was significantly depressed that activity was found in normal controls (P less than 0.01). 23 patients received intravesical BCG immuntherapy and NK activity was detected in the same patients 72 times in different period during the therapy. The authors decided that the activity of NK cells alters in BCG therapy. Increase of NK cells activity in the most common way of this alteration but many different type of this change is possible. The lower dose BCG (120 mg) often induce augmentation of NK activity but high dose BCG (200 mg) more frequently caused depressed activity of NK cells. The authors didn't find direct connection between therapy effect and NK activity but they found significantly less NK activity (P less than 0.03) in the patients who are in relapse. According to their opinions the role of natural killer cells in the antitumor effect of BCG can not be excluded. They recommended more immunological investigations to clear up the anticancer effect of BCG immuntherapy.