Allotypes of α₁‐antitrypsin in patients with cystic fibrosis, homozygous and heterozygous for deltaF508

In cystic fibrosis (CF) neutrophil released serine proteinase activity may facilitate Pseudomonas aeruginosa lung colonization, leading to chronic infection. Since such activity is mostly controlled by alpha 1-antitrypsin (alpha 1-AT), we postulated that with CF carrying deficient alpha 1-AT variants might be at higher risk for P. aeruginosa acquisition and might reveal other phenomena, specific for serine proteinase activity. In 215 Danish patients with CF, homozygous (80%) or heterozygous (20%) for the major CF mutation deltaF508, alpha 1-AT variants were determined. Carriage of deficient alpha 1-AT variants was correlated to an earlier onset of P. aeruginosa lung infection (P < 0.0001), higher total IgG (P < 0.0001), and P. aeruginosa-specific serum antibodies (P < 0.0001). The two groups did not differ in lung function, probably due to intensive antimicrobial treatment.