Pseudomonas-induced lung damage in cystic fibrosis correlates to bactericidal-permeability increasing protein (BPI)-autoantibodies

Abstract

Objective: Lung damage is the most common cause of death in cystic fibrosis (CF). It is induced by bacterial colonization and inflammatory activity perpetuates its course. Autoantibodies directed against BPI (bactericidal permeability increasing protein), called BPI-ANCA, have recently been associated with cystic fibrosis. Here we confirm this association and evaluate the relation between ANCA and total IgG level as they relate to bacterial colonization, pulmonary function, and musculoskeletal symptoms.

Methods: BPI-ANCA, MPO-ANCA, and PR3-ANCA were measured with ELISA in 46 adult patients with CF. Total IgG was determined by immunoturbidimetry. Results were correlated to bacterial colonization, lung function and musculoskeletal symptoms.

Results: BPI-ANCA was found in 33 patients. In the whole group, both BPI-ANCA and total IgG were inversely correlated to lung function, but in patients chronically colonized with Pseudomonas aeruginosa (P. aeruginosa), BPI-ANCA alone was correlated to lung damage (p = 0.01). Median lung function, measured as forced expiratory volume in 1 second, in P. aeruginosa colonized patients with high levels of BPI-ANCA was 43% of the predicted value. In BPI-ANCA negative, the corresponding figure was 83%. In patients not colonized with P. aeruginosa, this relation was less evident. No correlation between ANCA and musculoskeletal symptoms was seen.

Conclusion: P. aeruginosa induced lung damage in CF patients is associated with the presence of BPI-ANCA. P. aeruginosa colonized patients without BPI-ANCA have almost normal lung function. We suggest that BPI-ANCA discriminate P. aeruginosa colonized CF patients with severe lung damage from those whose disease is less destructive. Vasculitis like symptoms in CF are not ANCA associated.