Lung secretion sol-phase proteins: comparison of sputum with secretions obtained by direct sampling.

Publisher Website
Google Scholar
Abstract
Protein content of tracheal secretions and of bronchial lavage and bronchoalveolar lavage fluid was compared with that of sputum in 33 patients who underwent fibreoptic bronchoscopy. The secretion-to-serum concentration ratios for albumin, .alpha.1-antitrypsin, .alpha.1-antichymotrypsin and IgA fell progressively as samples were obtained from further down the bronchial tree, probably reflecting greater sample dilution. The secretion-to-serum protein ratios when standardized for the corresponding albumin ratio were similar in all secretions studied. IgA ratios were about 8 times those of albumin, and .alpha.1-antichymotrypsin ratios were about twice those of albumin, suggesting similar degrees of local production of these proteins in all secretions studied. Some patients showed considerable differences in IgA ratios between sputum and bronchial lavage fluid. The significance of these differences is not clear.