Prevalence and clinical significance of auto-antibodies in adults with cystic fibrosis.

The aim of this study was to determine the prevalence of different auto-antibodies in adult, French cystic fibrosis (CF) patients and to look for a correlation between autoimmunity, patient characteristics and survival. The sera of 144 patients were screened for a wide range of antibodies. Clinical, biological and bacteriological characteristics and the cystic fibrosis transmembrane conductance regulator genotype were recorded and progression of lung disease was examined. 113 (78.5%) patients displayed one or several auto-antibodies, predominantly immunoglobulin (Ig)A anti-Saccharomyces cerevisiae antibodies (ASCA; 43.7%) and antineutrophil cytoplasmic antibodies (ANCA; 40%), of which 59% showed bactericidal/permeability-increasing protein (BPI) specificity. The presence of BPI-ANCA was associated with the number of antibiotic courses, low body mass index, Pseudomonas aeruginosa colonisation, the presence of resistant P. aeruginosa, low forced expiratory volume in 1 s, CF-related liver disease, hypergammaglobulinaemia, male sex and inflammatory syndrome. The presence of ASCA-IgA was correlated with male sex and hypergammaglobulinaemia. 41 patients presented with chronic respiratory failure and/or requested lung transplantation or died during follow-up. These events were more frequent in patients with BPI-ANCA or ASCA-IgA. These findings confirm the high frequency of auto-antibodies in CF, particularly BPI-ANCA and ASCA-IgA, and the link between BPI-ANCA, severity of lung disease and CF prognosis.