Bronchial and alveolar exhaled nitric oxide as a marker of systemic involvement in patients with Crohn's disease

Background: Crohn9s Disease (CD) is an inflammatory bowel disease often associated with a variety of systemic manifestations, including airways involvement. Fractional Exhaled Nitric Oxide (FENO) can be measured non invasively at low (bronchial air) and high (alveolar air) flows to reflect proximal airway inflammation, and systemic inflammation. The aim of our study was to compare both bronchial and alveolar FENO as an index of pulmonary involvement and of systemic inflammation in CD patients with different stages of clinical activity, with a group of healthy subjects. Methods: Thirty CD patients (age 43.10±14.6 yrs) without clinical evidence of pulmonary diseases and 21 non smokers, not atopic healthy controls (age 35.1±13.2 yrs) were enrolled. Results: Bronchial (14.9±10.2 ppb vs 10.1±6.3 ppb, p=0.049) and alveolar FENO (4.4±2.2 ppb vs 2.6±1.9; p=0.006) were significantly higher in CD patients than in healthy controls, respectively. Both bronchial (p=0.0016) and alveolar FENO (p=0.017) were positively correlated with Crohn9s Disease Activity Index. Conclusions: Our results for bronchial and alveolar FENO confirm subclinical pulmonary involvement in Crohn9s disease. FENO may be of clinical value during follow-up of these patients as a surrogate marker of systemic inflammation.