Composition of bronchopulmonary secretions from patients with bronchiectasis.

Pulmonary function tests were carried out on 17 patients with bronchiectasis and six indices were selected to grade severity. Average concentrations of nine plasma proteins were determined by quantitative immunoelectrophoresis in specimens of sputum and serum from each patients. Wide patient-to-patient variation in concentration was encountered which appeared to follow a continuous progression unrelated to clinical severity. Patients at the upper end of the scale appeared to be responding by exudation and a pulmonary hypersensitivity reaction may be occurring in their lungs. There was evidence of selective concentration in sputum of alpha 1-antichymotrypsin and IgA although IgA concentrations were lower than would be expected in patients with chronic bronchitis. It is suggested that sputum IgA levels could be explored as a diagnostic criterion in those patients who could equally be suffering from chronic bronchitis.