Precipitating antibodies against Haemophilus influenzae and Staphylococcus aureus in sputum and serum from patients with cystic fibrosis

Serum and sputum sol phase from 23 patients with cystic fibrosis (CF) were examined for occurrence and titres of precipitins against Haemophilus influenzae and Staphylococcus aureus by means of crossed immunoelectrophoresis with intermediate gel. The patients had from four to nine H. influenzae precipitins in serum and in most cases fewer precipitins in sputum, but, on an average, there was no difference between the titres of the antibodies in serum and sputum. Most of the antibodies were cross-reactive with other species, notably those of the Haemophilus genus. S. aureus precipitins were generally found in higher numbers in serum than in sputum, but, on an average, the titre of the precipitins in sputum was higher than in serum. Three of the precipitins were detectable only in sputum and not in serum, and one of these is a S. aureus-specific precipitin. Most of the antibodies were cross-reactive with other species, and these antibodies were often present in sputum in much higher titres than in the corresponding sera. Antibodies against teichoic acid of the S. aureus cell wall could not be demonstrated in sputum, while they were present in 22 sera. The possible role of the local pulmonary humoral immune response in protective immunity and in the pathology of the lung disease in CF is discussed.