Siddiqui S, Gupta S, Cruse G, Haldar P, Entwisle J, Mcdonald S, Whithers P J, Hainsworth S V, Coxson H O, Brightling C
Institute of Lung Health, Leicester, UK.
Allergy. 2009 Jun;64(6):951-8. doi: 10.1111/j.1398-9995.2009.01951.x. Epub 2009 Feb 11.
Variable airflow obstruction and airway hyperresponsiveness (AHR) are features of asthma, which are absent in nonasthmatic eosinophilic bronchitis (EB). Airway remodelling is characteristic of both conditions suggesting that remodelling and airway dysfunction are disassociated, but whether the airway geometry differs between asthma and nonasthmatic EB is uncertain.
We assessed airway geometry by computed tomography (CT) imaging in asthma vs EB. A total of 12 subjects with mild-moderate asthma, 14 subjects with refractory asthma, 10 subjects with EB and 11 healthy volunteers were recruited. Subjects had a narrow collimation (0.75 mm) CT scan from the aortic arch to the carina to capture the right upper lobe apical segmental bronchus (RB1). In subjects with asthma and EB, CT scans were performed before and after a 2-week course of oral prednisolone (0.5 mg/kg).
Mild-moderate and refractory asthma were associated with RB1 wall thickening in contrast to subjects with nonasthmatic EB who had maintained RB1 patency without wall thickening [mean (SD) % wall area and luminal area mild-t0-moderate asthma 67.7 (7.3)% and 6.6 (2.8) mm(2)/m(2), refractory asthma 67.3 (5.6)% and 6.7 (3.4) mm(2)/m(2), healthy control group 59.7 (6.3)% and 8.7 (3.8) mm(2)/m(2), EB 61.4 (7.8)% and 11.1 (4.6) mm(2)/m(2) respectively; P < 0.05]. Airway wall thickening of non-RB1 airways generation three to six was a feature of asthma only. There was no change in airway geometry of RB1 after prednisolone. Proximal airway wall thickening was associated with AHR in asthma (r = -0.56; P = 0.02).
Maintained airway patency in EB may protect against the development of AHR, whereas airway wall thickening may promote AHR in asthma.
气流受限和气道高反应性（AHR）是哮喘的特征，而在非哮喘性嗜酸性粒细胞性支气管炎（EB）中不存在。气道重塑是这两种疾病的共同特征，提示重塑与气道功能障碍无关，但哮喘和非哮喘性EB之间的气道几何结构是否存在差异尚不确定。
我们通过计算机断层扫描（CT）成像评估哮喘和EB患者的气道几何结构。共招募了12例轻度至中度哮喘患者、14例难治性哮喘患者、10例EB患者和11名健康志愿者。受试者接受从主动脉弓到隆突的窄准直（0.75mm）CT扫描，以获取右上叶尖段支气管（RB1）。对于哮喘和EB患者，在口服泼尼松龙（0.5mg/kg）2周疗程前后进行CT扫描。
与非哮喘性EB患者保持RB1通畅且无管壁增厚相反，轻度至中度哮喘和难治性哮喘与RB1管壁增厚相关[平均（标准差）管壁面积和管腔面积，轻度至中度哮喘分别为67.7（7.3）%和6.6（2.8）mm²/m²，难治性哮喘分别为67.3（5.6）%和6.7（3.4）mm²/m²，健康对照组分别为59.7（6.3）%和8.7（3.8）mm²/m²，EB分别为61.4（7.8）%和11.1（4.6）mm²/m²；P<0.05]。仅哮喘患者存在3至6级非RB1气道的气道壁增厚。泼尼松龙治疗后RB1的气道几何结构无变化。哮喘患者近端气道壁增厚与AHR相关（r=-0.56；P=0.02）。
EB患者气道保持通畅可能预防AHR的发生发展；而气道壁增厚可能促使哮喘患者发生AHR。
