Non-invasive monitoring of airway inflammation after specific bronchoprovocation test with cat allergen in asthmatic patients

Introduction: The allergen bronchoprovocation is an important model to investigate asthma pathophisyology. Nitricoxide (NO) production is enhanced at sites of air way inflammation, leading increate exhaled NO(FeNO)as in asthma.The role of nasal NO in allergic inflammation is not yet clarified. Aims: To study air way and systemicinflammatory parameters in asthmatic patients after allergen bronchial challenge. Methods: Eleven non-moking patients with mild intermittent asthma, age 18-55 yrs,sensitised to cat dander were enrolled. Spirometry, induced sputum, FeNO at 50 ml/s flow rate, alveolar concentration (CalvNO), bronchial output (JawNO), nasal NO (nNO) and blood eosinophil count were obtained, before, 8 and 24 h after cat allergen bronchial challenge. Results: A significant increase at 8 and 24 h of FeNO(from 53.3 to 59.4,p<0.001; from 56.7 to 89.3, p=0.016) and JawNO (from 2.49 to 2.47, p=0.001; from2.67 to 3.97, p=0.017) were observed, together with an increase in sputum eosinophils (from 0.33to4.44%p=0.026)at24h.CalvNO correlated with blood (r=0.49, p=0.029) and bronchial eosinophilia (r=0.49,p=0.031). Nno correlated to FeNO both at 8h (r=0.67,p=0.001) and 24h (r=0.63,p=0.005). The degree of increase of nNO and FeNO (r=0.066, p=0.040) at 24h were correlated. Conclusions: Allergen exposure is associated with increase in bronchial NO production, which is related to sputum eosinophils.The correlation between the increase in nNO and FeNO suggest a link between bronchial and nose inflammation. The correlation between CalvNO, blood and sputum eosinophils, suggest a more peripheral airway inflammation, associated with systemic flogosis.