Serum proteins in sputum of patients with asthma

Immunoelectrophoretic and agar diffusion analyses of thirty-six asthma sputa and eighty-three nonasthma sputa were performed. Almost all specimens contained albumin and γ_1A-globulin as major serum protein components. Gamma-2 globulin was also detected in most cases. The ratio of γ_1A γ₂-globulin in sputum during convalescence was found to be much higher than this ratio in serum. The γ_1A-globulin, γ₂-globulin, and albumin in asthma sputum was increased compared to that in sputum from individuals without symptoms. A decrease in the γ_1A γ₂-globulin ratio in sputum was noted as a result of asthma attacks and/or infection in the upper respiratory tract. The significance of a high γ_1A γ₂-globulin ratio in sputum was discussed.