Fig. 1. The total number and aggregation of alveolar immune cells immediately after induction of anesthesia (open bars) and at the end of surgery (hatched bars) in nonsmokers (NS, n = 15), former smokers not smoking for 6–12 months (6–12, n = 15), for 3–5 months (3–5, n = 13), for 2 months (2, n = 13), and current smokers (S, n = 15). *Statistically significant differences (P < 0.01) from elapsed time zero. #Statistically significant difference (P < 0.01) from the nonsmokers at each time point. Data are expressed as mean ± SD.