Antitrypsin Deficiency in Pulmonary Disease: The Significance of Intermediate Levels

Abstract

Deficiency of serum alpha1 antitrypsin is inherited as an autosomal recessive trait, with the homozygous state manifested by severe deficiency and the heterozygous state by intermediate levels. Homozygotes often develop a distinctive form of pulmonary emphysema, although no correlation between severity of lung disease and severity of antitrypsin deficiency has been demonstrated within this group. The relationship of intermediate antitrypsin levels to lung disease is discussed. Three of 51 healthy persons and 17 of 146 consecutive patients with pulmonary disease had intermediate antitrypsin levels. This difference in prevalence is not statistically significant. The character of pulmonary disease in 18 intermediate patients and 13 severely deficient patients was compared with respect to clinical presentation, chest radiograph, pulmonary function abnormalities, and pattern of pulmonary perfusion. Dissimilarities in the two groups are described. These data suggest that intermediate antitrypsin levels are not important in the causation of pulmonary disease.