Activated complement in the sputum from patients with cystic fibrosis.

14 cystic fibrosis (CF) patients chronically infected with mucoid P. aeruginosa and 
presenting multiple precipitins in serum against this bacterium (CF + P) 
and 13 CF patients without P. aeruginosa infection (CF-P) had their 
plasma and sputum sol phase examined for albumin, Clq. C3/C3c, C4 
and C5 by means of electroimmunoassays. Their sputum sol phase was 
examined also for factor B by rocketimmunoelectrophoresis. C3c was demonstrated in 
the sputum sol phase but significantly more frequent (p less than 
0.01) among the CF + P patients than among the CF-P 
patients. Factor B was also demonstrated in the sputum sol phase, 
but no significant difference in frequency could be demonstrated between the 
CF + P and the CF-P patients. None of the results 
indicated that a local pulmonary production of complement factors took place. 
Complement activation was significantly (p less than 0.01) associated with inflammation 
expressed as increased (formula: see text). The results show the importance 
of complement mediated inflammation in the pathogenesis of pulmonary tissue damage 
in patients with CF and support the concept of chronic P. 
aeruginosa lung infection as an immune complex disease in CF patients. 
