Healthy Lifestyles Are Associated with Higher Lymphokine-Activated Killer Cell Activity

Background.To investigate the association between lifestyle factors and immune responses to tumors, we determined lymphokine-activated killer (LAK) cell activity and proportions of lymphocyte subsets in 54 healthy males. Methods.LAK cell activity was determined by51Cr release assay. The proportions of natural killer cells (CD3−16+56−, CD3−16−56+or CD3−16+56+cells), helper/inducer T cells (CD4+8−), and cytotoxic/suppressor T cells (CD4−8+) in lymphocytes were also determined by flow cytometry. Subjects were classified into two groups, good or poor overall lifestyle, according to their answers on a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, physical exercise, mental stress, sleeping pattern, nutritional balance, eating breakfast, working pattern). Results.Subjects with good health practices regarding smoking showed significantly higher LAK cell activity. They also showed a significantly higher proportion of natural killer cells and a lower proportion of helper/inducer T cells. LAK cell activity was significantly higher in subjects with a good overall lifestyle than in those with a poor overall lifestyle after controlling for the effects of smoking. There were no significant differences in the proportions of lymphocyte subsets between the two lifestyle groups. Conclusions.Lifestyle factors are associated with LAK cell activity and the proportion of lymphocyte subsets.