[Quantitative determination of IgA from human bronchial mucus (author's transl)].

Before quantitative analysis of bronchial mucus proteins, sputum must be transformed into a homogeneous medium: this is done by ultrasonic action and contact with cationic resin AG 50 W X 2. Then, acid mucins are fixed on Ecteola-cellulose, and proteins extracted by a phosphate/saline buffer at pH 5. IgA is estimated by electroimmunodiffusion. Reproducibility of the method is discussed: the accuracy for IgA values is 4%.