Correlation of serum opsonic activity in cystic fibrosis with colonization and disease state: measurement of opsonins to Pseudomonas aeruginosa by neutrophil superoxide anion generation

Serum from patients with cystic fibrosis and normal controls was used to opsonize mucoid and nonmucoid Pseudomonas aeruginosa particles. Opsonic activity was then determined by measuring the production of superoxide anion (O2-) from normal neutrophils stimulated with the opsonized particles. Without any opsonization, mucoid P. aeruginosa stimulated significantly more O2- than nonmucoid P. aeruginosa. Responses to nonmucoid P. aeruginosa observed with heat-inactivated serum from patients with cystic fibrosis were significantly higher (p = 0.008) than those observed with heat-inactivated control sera. Comparisons made between patients who were colonized with P. aeruginosa and those who were not showed that heat activated serum from colonized patients had significantly higher levels of opsonic activity than heat inactivated serum from patients who were not colonized. These differences were observed with either mucoid or nonmucoid P. aeruginosa. A negative correlation was also observed between opsonic activity and clinical status measured by Schwachman scores of colonized patients. These data indicate that in patients colonized with P. aeruginosa the deterioration of their clinical status correlated with increased opsonic activity reflected in the oxidative burst response of neutrophils.