Smoking and interleukin-1 activity released from human alveolar macrophages in healthy subjects

To evaluate the activation of alveolar macrophages from smoking, we studied interleukin-1 (IL-1) activity released from alveolar macrophages in eight healthy smokers, compared to 12 healthy nonsmokers. We used 24-hour culture supernatants containing IL-1 of bronchoalveolar lavage fluid (BALF) macrophages/blood monocytes with or without LPS stimulation. Using C3H/HeJ thymocyte PHA costimulation assay, we found that IL-1 activity released from LPS stimulated BALF macrophages was significantly higher in smokers (2.39 +/- 0.33 U/ml) than in nonsmokers (1.47 +/- 0.19 U/ml, p less than 0.05). We also detected IL-1 inhibitory activity in supernatants by using IL-1 inhibitory assay. The inhibitory activity was higher in nonsmokers than in smokers especially under LPS stimulation. The presence of inhibitory factors other than prostaglandin-E2 was suggested from the differential response to the addition of indomethacin into cultures from nonstimulated and LPS-stimulated supernatants of BALF macrophages.