Immunoserology of Pseudomonas aeruginosa infections in man. III. Site of infection, duration of the presence of Pseudomonas aeruginosa and antibody response.

In 39 patients of a respiratory intensive care unit the intensity of the serological response to the purified LPS of the causative Pseudomonas aeruginosa was found to change according to the site of infection. The highest titres were found in septic cases, when the antigenic assault reached all the immune-competent cells in the body. Short presence (only one positive bacteriological culture) of P. aeruginosa at the site of inflammation resulted in a low or moderate rise in antibody titre. Ten days were enough for the development of a maximum total antibody (approximately IgM) response, while IgG type antibodies moderately grew further when the presence of P. aeruginosa lasted more than 10 days. Only a 16-fold increase in total antibodies per se or a 4-fold rise in both total (approximately IgM) and IgG antibodies confirmed the pseudomonas infection.