Beneficial effects of interleukin-2 on natural killer activity in lung cancer patients

The effects of human interleukin-2 (IL-2) on the growth and natural killer (NK) activities of lymphocytes were evaluated in patients with advanced lung cancer, and compared with age-matched normal subjects. Peripheral blood lymphocytes (PBL) from the patients and the controls were grown exponentially in response to IL-2 and showed no differences in the cell numbers and the proliferative capacities. In both groups, pretreatment for 18 hr with IL-2 was able to augment the NK activity of PBL. Furthermore, PBL propagated in IL-2 over a period of 15 days also demonstrated vigorous NK activity, although there was a relative broad range of NK levels among those from the patient individuals. The present study suggests that the depressed NK activity of PBL from our patients can not be explained by lack of their responsiveness to IL-2, and that human IL-2 can augment the NK activity of PBL and support the growth of PBL-derived cells with high NK levels in patients with lung cancer.