Plasma proteins of the bronchoalveolar surface of the lungs of smokers and nonsmokers.

Plasma proteins were measured in bronchoalveolar lavage effluents and serums from normal healthy nonsmokers and smokers, and their concentrations in the 2 fluids were compared. Two-dimensional polyacrylamide gel electropherograms suggested, and radial immunodiffusion assays confirmed, that the soluble proteins of the bronchoalveolar surface resemble serum in kind and amount with the following significant exceptions. Two immunoglobulins, IgG and IgA, were present in amounts that exceeded their concentrations in serum; of the 2, IgG was more abundant. Large nonimmunoglobulin proteins (greater than 300,000 daltons) were absent or present at very low concentrations compared with the amounts found in serum. Transferrin was the only nonimmunoglobulin with a concentration significantly higher at the bronchoalveolar surface than in serum. Smoking did not cause a significant change in the concentration of any protein in serum, but did cause an increase in IgG, C4, and C3 and a decrease in alpha 2-thioglycoprotein, alpha 1-acid glycoprotein, and Gc-globulin in lavage effluents from females.