Sputum and serum calprotectin are useful biomarkers during CF exacerbation.

BACKGROUND Adequate monitoring of cystic fibrosis lung disease is difficult. CF exacerbation offers a unique setting to test the utility of biomarkers in the assessment of changing airways inflammation. We hypothesised that levels of calprotectin in sputum (and serum) would change informatively following treatment of an exacerbation. METHODS 27 patients with CF were recruited at onset of pulmonary exacerbation. Sputum and serum were collected at the start and end of anti-biotic therapy. Sputum calprotectin, interleukin-8 (IL8), and myeloperoxidase (MPO) were measured, as were serum calprotectin, CRP and vascular endothelial growth factor (VEGF). RESULTS Sputum calprotectin decreased following treatment of an exacerbation (p<0.05), and was superior to other sputum markers. Serum calprotectin, CRP, and VEGF also decreased significantly (p=0.002, p=0.002, p=0.013 respectively). Serum calprotectin level following treatment had predictive value for time to next exacerbation (p=0.032). CONCLUSIONS This study demonstrates the superiority of calprotectin (in sputum and serum) as a biomarker of CF exacerbation over better-established markers.