Non-asthmatic eosinophilic bronchitis is characterized by proximal airway eosinophilic inflammation as compared with classic asthma and cough variant asthma

Non-asthmatic eosinophilic bronchitis (NAEB) is a common cause of chronic cough . NAEB involves eosinophilic airway inflammation, which manifests as sputum eosinophilia similar to that in cough variant asthma (CVA), in which cough presents as the sole manifestation, or in classic asthma (CA) which is characterized by wheezing, dyspnea and cough . However, NAEB lacks the airway hyperresponsiveness associated with asthma. The mechanism underlying these different clinical features remains unclear. A few studies have investigated pathological changes in the airways of patients with NAEB . A higher degree of mast cell infiltration was showed in the airway smooth muscle of asthmatic patients than that of NAEB , indicating that the site and degree of inflammatory cell infiltration may differ between NAEB and asthma. However, biopsies in previous studies were taken at a single site within the airway, and this may have prevented a full view of the differences in both the proximal airway and the periphery airway. Whether the degree of inflammation at different sites within the airway were different between NAEB and asthma remains unknown.