Erythrocytes prevent inactivation of alpha 1-antitrypsin by cigarette smoke.

Red blood cells (RBC) possess strong antioxidant activity. We tested whether this activity was sufficient to prevent the oxidative inactivation of alpha 1-antitrypsin (alpha 1-AT) by cigarette smoke. We found that RBC in physiological concentrations completely prevented the inactivation of alpha 1-AT. The major erythrocytic antioxidants, catalase, superoxide dismutase and glutathione were then selectively inhibited and the RBC retested. Only the inhibition of catalase significantly impaired the protective ability of added erythrocytes. We suggest that RBC antioxidants may be an important variable in determining the degree of protection of alpha 1-AT against oxidation.