Background: Chronic smoking influences bronchoalveolar lavage fluid (BALF) cell profiles in healthy subjects, which may alter profiles of inflammatory and regulatory cytokines.
Objective: We focused on the evaluation of smoking-related changes in the amounts of cytokines released from BALF macrophages.
Methods: We measured the amounts of immunoreactive culture supernatants by using ELISA.
Results: The amounts of IL-1 receptor antagonist (IL-1ra) were lower in smokers [n = 10, median 22.1 ng/ml, 25th and 75th percentiles (18.7-39.1)] than in nonsmokers [n = 10, 48.6 (39.2-66.1), p = 0.010]. In smokers, lipopolysaccharide stimulation revealed decreases in the amounts of interleukin-6 (IL-6) [nonsmokers: 2.1 ng/ml (0.68-5.4 vs. smokers: 0.5 (0.03-0.87), p = 0.049] as well as IL-1ra [nonsmokers: 69.2 ng/ml (48.3-83.8) vs. smokers: 27.3 (17.2-56.7), p = 0.028]. A delay in release from intracellular storage was not the cause of the reduced amounts of IL-1ra. In addition, interleukin-1beta (IL-1beta) was positively correlated with IL-6 and granulocyte macrophage colony-stimulating factor in nonsmokers, but not in smokers. Furthermore, the decreases in IL-1ra and interleukin-8 were correlated with the increase in the number of BALF macrophages in smokers, but not in nonsmokers.
Conclusions: Chronic smoking caused changes in the profiles of cytokines released from BALF macrophages in healthy subjects. Decreases in the amounts of regulatory cytokines, but not prominent changes in the amounts of inflammatory ones, were characteristic.