Non-asthmatic eosinophilic bronchitis (NAEB) is a common cause of chronic cough¹. 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 cough¹. 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 NAEB². A higher degree of mast cell infiltration was showed in the airway smooth muscle of asthmatic patients than that of NAEB³, 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.

中文翻译：

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与经典哮喘和咳嗽变异性哮喘相比，非哮喘性嗜酸性支气管炎的特征是近端气道嗜酸性炎症

非哮喘性嗜酸性支气管炎 (NAEB) 是慢性咳嗽的常见原因¹。NAEB 涉及嗜酸性气道炎症，表现为痰液嗜酸性粒细胞增多，类似于咳嗽变异性哮喘 (CVA)，其中咳嗽是唯一表现，或典型哮喘 (CA)，其特征是喘息、呼吸困难和咳嗽¹。然而，NAEB 缺乏与哮喘相关的气道高反应性。这些不同临床特征背后的机制仍不清楚。^{一些研究调查了 NAEB 2}患者气道的病理变化。哮喘患者气道平滑肌中肥大细胞浸润程度高于NAEB ³，表明炎症细胞浸润的部位和程度在 NAEB 和哮喘之间可能不同。然而，先前研究中的活检是在气道内的单个部位进行的，这可能妨碍了对近端气道和外周气道差异的全面观察。NAEB 和哮喘之间气道内不同部位的炎症程度是否不同仍然未知。