Natural killer and interleukin-2 induced cytotoxicity in asthmatics. I. Effect of acute antigen-specific challenge.

Natural killer (NK) cell activity and interleukin-2 (IL-2) induced cytotoxicity to NK-resistant targets T24 in a group of patients with grass pollen seasonal asthma were investigated. Acute bronchial provocation with this antigen was also performed and blood samples were taken before and 15 min after the maximal clinical response. NK activity was elevated in this group but there was a significant decrease after acute challenge. IL-2 induced cytotoxicity was also increased and declined after antigen challenge. Limiting dilution analysis for minimal frequencies of precursors of the IL-2 induced killer cells was introduced and showed increased numbers of lymphokine-activated killing precursors in this group of patients. These data might indicate the aberrations of the IL-2 system in immediate type allergy but the clinical significance of these findings remains to be determined.