Immunoglobulins, complement and arylsulphatase in sputum from chronic bronchitis and other pulmonary diseases.

The immunoglobulins IgG, IgA, IgM and IgE and the individual complement (C) components C3 and C4 were measured in the sputum and serum from twenty-six patients with chronic bronchitis, twenty asthmatics who were skin test-positive, six who were skin test-negative, seven patients with bronchiectasis, fifteen with bronchial carcinoma and five with pneumonia. Apart from raised serum concentrations of IgE in skin test-positive asthmatics, the serum concentrations of immunoglobulins G, A and M were, in general, similar for all patient groups. In all subjects except those with bronchiectasis, sputum IgG was present in small amounts, whereas IgM was usually undetectable. IgA (7S) was detected in all of the sputum samples examined; three of the bronchiectatics having particularly high values. Appreciable amounts of IgE were found in the sputum from many chronic bronchitics and skin test-positive asthmatics, but in only a few in the other groups. Sputum C3 and C4 concentrations were low or undetectable in all groups. When the immunoglobulin or complement concentrations were expressed as a sputum/serum ratio, high values were obtained for IgA in all patients groups. Compared to the other diseases, IgE ratios were elevated in chronic bronchitis and IgM ratios in bronchiectasis. Arylsulphatase IIB was also measured in the sputum and was considerably higher in bronchiectasis than in the other pulmonary disorders, consistent with the greater inflammatory changes in this condition. These data support our previous findings on an association between IgE and chronic bronchitis.