Precipitating antibodies against E. coli, B. fragilis, and P. aeruginosa in CF patients and normal persons determined by means of crossed immunoelectrophoresis.

Wallwork and co-workers have proposed that increased absorption of antigens takes place 
across the mucosal membranes of the gut and respiratory tract possibly 
due to a transient defect in the production of secretory IgA. 
As a consequence of this hypothesis, one would expect cystic fibrosis 
patients to produce a pronounced antibody response against the intestinal bacterial 
flora. The present work was therefore carried out to investigate the 
antibody response in CF patients and in normal persons against Escherichia 
coli and Bacteroides fragilis which are present in the gut in 
large numbers and against the respiratory pathogen P. aeruginosa. A significantly 
higher prevalence of precipitins against each of the 3 bacterial species 
was found in CF patients compared to normal persons, and the 
prevalence of precipitins against each of these bacteria increased significantly with 
age. As regards P. aeruginosa precipitins, the prevalence and number was 
significantly higher in CF patients who have subsequently succumbed compared to 
CF patients who are still alive. Such a correlation between the 
antibody response and the prognosis of the patients was not found 
as regards E. coli or B. fragilis. Considering the hypothesis of 
Wallwork and co-workers concerning increased absorption of antigens from the gut, 
it seems more attractive to suppose that increased absorption of antigens 
from the gut flora occurs predominantly in CF patients with P. 
aeruginosa lung infection with a pronounced antibody response against P. aeruginosa. 
