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. 