Acute effect of smoking on the functional activity of alpha1-protease inhibitor in bronchoalveolar lavage fluid.

To assess the acute effect of smoking on the functional activity of alpha1-protease inhibitor (alpha-Pl) in bronchoalveolar lavage (BAL), we studied 38 smokers (mean age 25 +/- 6.5 yr), who had 2 fiberoptic bronchoscopic lavages in sequence, the first after 8 h of abstinence from smoking, and the second at varying time intervals after smoking. Twenty-two smokers were tested before, and 10 min to 3 h after, smoking 2 medium-tar filter cigarettes; 16 smokers were were tested before, and 2 min to 60 min after, smoking 4 cigarettes. Eight nonsmoking volunteers had 2 BAL performed in sequence as control subjects. Initial BAL from control subjects and from smokers after 8 h of abstinence had similar alpha-Pl activity (mean 0.495 +/- SD 0.017 micrograms of pancreatic elastase/micrograms alpha-Pl, about 90% of the activity of purified alpha-Pl). After smoking, we did not find significant inactivation of alpha-Pl except in the 6 smokers lavaged 1 h after smoking 2 cigarettes, whose alpha-Pl activity decreased slightly to 90.0 +/- SD 10.6% of their initial activity (p less than 0.05). We also obtained BAL from 7 smokers only after smoking, and did not find inactivation of alpha-Pl. We conclude that in young healthy smokers: (1) alpha-Pl in BAL after 8 h of abstinence from smoking is active similar to nonsmoking control subjects, and (2) after smoking 2 to 4 cigarettes, there is no, or very limited, inactivation of alpha-Pl.