Autoantibody response to BPI predict disease severity and outcome in cystic fibrosis.

BACKGROUND: Autoantibodies against bactericidal permeability increasing protein (BPI-ANCA) are frequently present in cystic fibrosis patients and have been reported to be associated to colonization with Pseudomonas (P) aeruginosa and lung damage. In the present study, we investigated BPI-ANCA as a prognostic marker and its relation to P. aeruginosa colonization and lung function. METHODS: BPI-ANCA, measured by ELISA, was examined relative to lung function and microbiological findings. The prognostic value of BPI-ANCA was assessed in 46 adult patients followed for 1.2-8.9 years. The cross-sectional investigation was performed in 366 patients (age 0.5-55). RESULTS: The presence of BPI-ANCA predicted poor prognosis. An adverse outcome occurred in 15/28 BPI-ANCA positive patients and in 2/18 BPI-ANCA negative patients (p=0.01). This result remained valid when the patients were stratified according to lung function (p=0.03). Findings of BPI-ANCA were correlated to P. aeruginosa colonization and lung damage. Development of BPI-ANCA occurred after colonization with P. aeruginosa. All colonized patients did not develop BPI-ANCA. The BPI-ANCA levels were fairly stable during the disease course, but decreased significantly following lung transplantation. CONCLUSION: BPI-ANCA responses follow colonization with P. aeruginosa and may be predictive for lung damage.