Perzanowski Matthew S, Yoo Young
Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, N.Y., USA.
Int Arch Allergy Immunol. 2015;166(2):107-13. doi: 10.1159/000375237. Epub 2015 Mar 13.
There is increasing interest in the role of indirect bronchial challenges because clinical studies have shown that indirect airway hyperresponsiveness (AHR) reflects underlying airway inflammation better than direct AHR. Fractional exhaled nitric oxide (FeNO) appears to be a useful clinical tool for assessing airway inflammation noninvasively. We examined whether FeNO is more closely related to AHR to indirect stimuli than AHR to direct stimuli in children with mild to moderate asthma.
Fifty-nine asthmatic children aged 6-16 years without rhinitis, underwent spirometry, FeNO measurement and blood tests for serum total IgE, blood eosinophil count and serum eosinophil cationic protein (ECP). All subjects underwent methacholine and adenosine 5-monophosphate (AMP) challenge tests at intervals of 3 days.
In a univariate linear regression analysis, FeNO was significantly associated with both PC20 AMP (R(2) = 0.341, p < 0.001) and PC20 methacholine (R(2) = 0.188, p = 0.001). After adjustment for age, sex, serum total IgE and blood eosinophil count, the association between FeNO and PC20 AMP (β = -1.98, p = 0.001) was more robust than that between FeNO and PC20 methacholine (β = -0.87, p = 0.081). The significant correlation between FeNO and PC20 AMP was observed in the steroid-naïve group (β = -2.48, p = 0.001), but not in the steroid-treated group (β = 0.88, p = 0.463).
FeNO levels were more closely associated with PC20 AMP than with PC20 methacholine. This relationship could only be seen in the steroid-naïve subjects. These results suggest that FeNO levels in children with asthma may be more closely related to indirect AHR than to direct AHR.
间接支气管激发试验的作用日益受到关注，因为临床研究表明，间接气道高反应性（AHR）比直接AHR能更好地反映潜在的气道炎症。呼出一氧化氮分数（FeNO）似乎是一种用于无创评估气道炎症的有用临床工具。我们研究了在轻度至中度哮喘儿童中，FeNO与间接刺激的AHR的相关性是否比与直接刺激的AHR更密切。
59名年龄在6至16岁、无鼻炎的哮喘儿童接受了肺功能测定、FeNO测量以及血清总IgE、血液嗜酸性粒细胞计数和血清嗜酸性粒细胞阳离子蛋白（ECP）的血液检测。所有受试者每隔3天接受一次乙酰甲胆碱和5-单磷酸腺苷（AMP）激发试验。
在单变量线性回归分析中，FeNO与AMP的PC20（R(2)=0.341，p<0.001）和乙酰甲胆碱的PC20（R(2)=0.188，p=0.001）均显著相关。在调整年龄、性别、血清总IgE和血液嗜酸性粒细胞计数后，FeNO与AMP的PC20之间的关联（β=-1.98，p=0.001）比FeNO与乙酰甲胆碱的PC20之间的关联（β=-0.87，p=0.081）更强。在未使用类固醇的组中观察到FeNO与AMP的PC20之间存在显著相关性（β=-2.48，p=0.001），但在使用类固醇治疗的组中未观察到（β=0.88，p=0.463）。
FeNO水平与AMP的PC20的相关性比与乙酰甲胆碱的PC20更密切。这种关系仅在未使用类固醇的受试者中可见。这些结果表明，哮喘儿童的FeNO水平可能与间接AHR的相关性比与直接AHR的相关性更密切。
