The effect of specific and nonspecific immunotherapy on natural killer cell activity in patients with non-small-cell lung cancer.

Fourteen patients with stages I and II non-small-cell lung carcinoma receiving adjuvant immunotherapy after surgery were studied serially for natural killer (NK) cell cytotoxicity assays. Seven patients received active nonspecific immunotherapy with Freund's complete adjuvant alone and seven patients received active specific immunotherapy with tumor-associated antigen plus Freund's complete adjuvant. Both groups were analyzed as a single group in view of the lack of any difference in the results. The results indicated that NK-cell cytotoxicity v K562 was lower in untreated patients than in normal controls, but the difference was not significant. There was no evidence of specific cytotoxicity v the lung cell line A549 in untreated patients when compared with normal controls. Compared with pretreatment values, elevated cytotoxicity v both K562 and A549 was observed at every post-treatment time point tested, and this was statistically significant at several time points by a paired t test. No specific effect was noted after immunization with lung antigen on cytotoxicity against the lung cell line A549. Other correlations studied did not show any relationship between delayed hypersensitivity skin testing or serum carcinoembryonic antigen levels and NK-cell cytotoxicity. It is concluded that NK-cell reactivity was increased nonspecifically by active specific and nonspecific immunotherapy. This increase seems to peak at the 12-month period and was significant when compared with pretreatment levels.