Lung function in alpha1-antitrypsin heterozygotes (Pi type MZ).

Abstract

Whether or not α1-antitrypsin heterozygotes are abnormally predisposed to lung disease is controversial. To define the pulmonary status of the heterozygote Pi type MZ, results of lung function studies performed in 54 adults of Pi type MZ were compared to those performed in a control group of 69 adults with Pi type MM. The MZ adults had significantly inferior function by the following indices: arterial oxygen tension, lung elastic recoil, maximal expiratory flows, and closing capacity. The MZ lifetime nonsmokers had significantly lower arterial oxygen tensions and flows than MM nonsmokers. The pulmonary function changes in the MZ group were consistent with those of early emphysema. Cigarette smoking and Pi type MZ interacted additively and caused greater reduction in function than either factor produced independently. It was concluded that the Pi type MZ is a significant risk factor in lung disease.