Relevance between clinical status and exhaled molecules related to neutrophilic inflammation in pediatric cystic fibrosis

Introduction: Cystic fibrosis (CF) is characterized with chronic inflammation with neutrophil and related cytokines in airway secretions. We aimed to measure the levels of neutrophil related inflammatory markers as nitric oxide, IL-8, IL-17, leukotriene B4 and neutrophil elastase as well as e-cadherin in exhaled breath condensate (EBC) and to determine their relation with clinical findings. Methods: We consecutively enrolled cystic fibrosis patients in our clinics aged above five years who could cooperate for exhaled breath condensate to this case-control study (n=30). The age and sex matched control group (n=26) was enrolled. Spirometry was performed during the stable period and EBC samples were obtained for measurement of the markers. Results: Mean age of the subjects enrolled was 12.1(4.2) years and 40% were positive for pseudomonas aeruginosa in sputum. Subjects who had pseudomonas aeruginosa in sputum cultures had significantly lower FEV1, FVC and FEF 25/75 values compared to the ones without pseudomonas aeruginosa (p=0.002, p=0.002 and p=0.005 respectively). EBC neutrophil elastase levels were significantly higher in the CF patients compared to non-CF controls (3.11 ±4.71 vs 0.90 ±2.68, p=0.04). Nitric oxide, IL-17, IL-8, e-cadherin, neutrophil elastase or leukotriene B4 levels in EBC of CF patients were not related to pseudomonas infection, FEV1 levels or hospital admission in the last year. Conclusion: In our study, neutrophil elastase levels in EBC are higher in CF patients compared to non-CF controls. This is independent of acute infection and is evidence to persistence of neutrophilic lung injury. However, EBC NO, IL-8, IL-17, e-cadherin, neutrophil elastase and leukotriene B4 levels as inflammatory markers, are not correlated with disease progression or clinical findings.