Amount and avidity of IgG antibodies toPseudomonas aeruginosa exotoxin A antigen in cystic fibrosis patients

Abstract

Amount and avidity of serum IgG antibodies to Pseudomonas aeruginosa exotoxin A in sera of 31 patients with cystic fibrosis (CF) was studied. Eight patients had P. aeruginosa isolated from the sputum on multiple occasions, while from 23 patients no P. aeruginosa was isolated. Amount of IgG antibodies to P. aeruginosa exotoxin A were significantly increased in the serum of patients with P. aeruginosa pulmonary colonization (p<0.0001). On the contrary, serum IgG avidity in the colonized and in the non-colonized CF patients was low (<10) and was statistically different when compared to the 30 age-matched healthy controls (p<0.0001). There was no change in IgG avidity in six chronically infected CF patients from whom we obtained serum samples after half a year period (p=0,55).

IgG avidity to Pseudomonas aeruginosa over the course of chronic lung biofilm infection in cystic fibrosis

“…The mechanisms leading to low effectiveness of the humoral immune response against P. aeruginosa are poorly understood. A low opsonizing capacity of CF antibodies have been evidenced and some reports point to their low avidity [5][6][7]. Nevertheless, there is a gap of almost two decades regarding to this subject and very few studies have addressed the humoral mechanisms of the CF immune response since then.…”