CRP and cystic fibrosis: Furthermore, the presence of ANCA in children with CF is associated with indirect measures of disease severity, including low forced expiratory volume (FEV1), P. aeruginosa colonization, presence of multi-drug resistant bacteria or pan-resistant P. aeruginosa, the number of antibiotic courses received, the presence of CF-related liver disease, hypergammaglobulinemia, elevated C-reactive protein, and low BMI (28).