Quantitation of proteins in sputum from patients with chronic obstructive lung disease. I. Determination of immunoglobulin A.
Samples of sputum from nine patients with chronic obstructive lung disease were collected every morning for 5 consecutive days, and their mean apparent viscosities were determined. After a standard solubilization procedure, the concentration of immunoglobulin A (IgA) in each sample was determined by quantitative immunodiffusion and also by an immunofluorimetric method, using dimeric IgA purified from colostrum as a standard. The two methods gave diverging results probably reflecting different sensitivities of the techniques to various classes of IgA (monomers, dimers and polymers). The concentration of IgA was found to vary from 1.2 to 3.9 g/l with a mean value of 2.3 g/l for the 45 samples using the immunodiffusion technique, and from 1.3 to 4.9 g/l with a mean value of 3.5 g/l using the immunofluorimetric method. In agreement with earlier observations, a weak correlation was shown between the concentration of IgA in the samples and their mean viscosities. A similar correlation was, however, demonstrated between IgA and the total content of protein in the soluble part of the samples. It could therefore not be decided whether IgA itself or other proteins in the sputa were responsible for the observed effect on viscosity.
D002241:Carbohydrates / Q000032:analysis; D003126:Colostrum / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D005779:Immunodiffusion; D007070:Immunoglobulin A / Q000032:analysis*; D008173:Lung Diseases, Obstructive / Q000276:immunology* / Q000473:pathology; D011506:Proteins / Q000032:analysis; D013183:Sputum / Q000032:analysis / Q000276:immunology*; D014783:Viscosity
D002241:Carbohydrates; D007070:Immunoglobulin A; D011506:Proteins