Serum levels of alpha 1-antitrypsin and Pi types in children with bronchiolitis.

Alpha 1-antitrypsin levels were determined at the beginning of the disease and after clinical recovery in a group of 51 infants with bronchiolitis, and the results were compared to those obtained in 24 normal infants and in 15 infants with viral bronchopneumonia. Distribution of Pi types in the patients with bronchiolitis was also compared to that observed in a control population of 170 blood donors of the same ethnic background. Both serum levels of alpha 1-antitrypsin and prevalence of non-M phenotypes were not statistically different from the values found in the control groups, thus not supporting the hypothesis that a deficiency of alpha 1-antitrypsin plays a role in the pathogenesis of bronchiolitis. A non explained finding was the lack of elevation of serum level of alpha 1-antitrypsin during the acute phase of the bronchiolitis process, a fact present in the group of patients with bronchopneumonia.