IgA and IgG antibodies against surface antigens of Pseudomonas aeruginosa in sputum and serum from patients with cystic fibrosis.

Eleven cystic fibrosis (CF) patients chronically infected in the lungs with mucoid 
Pseudomonas aeruginosa and presenting multiple precipitins in serum against this bacterium 
(CF + P) and 10 CF patients without P. aeruginosa infection 
(CF-P) had their serum and sputum sol phase specimens examined for 
antibodies of the IgA and IgG classes against surface antigens of 
P. aeruginosa by means of an indirect immunofluorescence technique. Both the 
IgA and IgG antibody titres demonstrated in serum and sputum of 
the CF + P patients were significantly higher than in those 
of the CF-P patients (p less than 0.01). The titre of 
IgA antibodies in the sputum was higher than in serum in 
3 cases indicating local pulmonary production of specific IgA antibodies. The 
role of the demonstrated antibodies in the local pulmonary immune defense 
mechanisms and the possible patogenesis of the pulmonary tissue damage in 
CF patients is discussed. 