Two dimensional protein patterns of bronchoalveolar lavage fluid from non-smokers, smokers, and subjects exposed to asbestos

Background - Bronchoalveolar lavage (BAL) fluid contains a large number of proteins which comprise a potential resource for studying respiratory effects due to occupational and environmental exposures. A study was undertaken to compare protein patterns of BAL fluid from nonsmokers, smokers, and subjects exposed to asbestos. Methods - BAL fluid samples were analysed with two dimensional gel electrophoresis (2-DE). The separated proteins were detected, quantified, and pattern-matched between different individuals with a computerised imaging system designed for evaluations of 2-DE patterns. Results - About 200 different protein spots were detected in each sample of BAL fluid. As is the case with blood plasma, the BAL fluid samples contained large amounts of albumin, transferrin, and immunoglobulins. Higher levels of basic proteins were found in smokers than in non-smokers, while subjects exposed to asbestos had increased amounts of several high molecular weight proteins as well as basic proteins. Lower levels of albumin and higher levels of immunoglobulins were found in smokers than in nonsmokers, while higher levels of transferrin were found in asbestos exposed subjects than in unexposed subjects. Moreover, in the group exposed to asbestos differences were found between patients with pleuritis and patients with pleural plaque, and one protein spot was found only in two patients with progressive pleural disease. Conclusion - These results suggest that both smokers and asbestos exposed subjects have significant changes in their airway protein expression compared with non-smokers and unexposed subjects. It is inferred that analysis of protein patterns in the BAL fluid with 2-DE may be used to detect and characterise, at a molecular level, respiratory effects due to occupational and environmental exposures.