Gao Jie, Wu Feng
Department of Respiratory Medicine, The Third People's Hospital, Guangzhou Medical College, 1# Xuebei Ave., Huizhou, 516002 Guangdong China.
Allergy Asthma Clin Immunol. 2018 May 23;14:21. doi: 10.1186/s13223-018-0248-7. eCollection 2018.
The fractional exhaled nitric oxide (FeNO) and blood eosinophils are biomarkers of eosinophilic airway inflammation used in the diagnosis and management of asthma, although induced sputum is the gold standard test for phenotypic asthma. Nevertheless, the clinical application of the correlation between sputum eosinophils, FeNO and blood eosinophils is controversial.
To investigate the clinical application of the correlation between sputum eosinophils, FeNO and blood eosinophils with uncontrolled asthmatic patients. It also examined the relationships between these biomarkers in bronchial reversibility and bronchial hyper-responsiveness (BHR).
This study evaluated 75 uncontrolled asthmatic patients (symptom control and future risk of adverse outcomes). All patients underwent the following on the same day: FeNO, spirometry, BHR or bronchodilator reversibility, sputum induction and blood collection. Eosinophilic airway inflammation was defined as sputum eosinophils ≥ 2.5% or FeNO levels ≥ 32 parts per billion (ppb).
A significant positive relationship was between percentage of sputum eosinophils and FeNO (r = 0.4556; p < 0.0001) and percentage of blood eosinophils (r = 0.3647; p = 0.0013), and a significant negative correlation was between percentage of sputum neutrophils and FeNO (r = - 0.3653; p = 0.0013). No relationship between FeNO and percentage of blood eosinophils (p = 0.5801). ROC curve analysis identified FeNO was predictive of sputum eosinophilia [area under the curve (AUC) 0.707, p = 0.004] at a cutoff point of 35.5 ppb (sensitivity = 67.3%, specificity = 73.9%). Percentage of blood eosinophils was also highly predictive with an AUC of 0.73 (p = 0.002) at a cut-off point of 1.5%, sensitivity and specificity were 61.5 and 78.3%, respectively. Although the sputum neutrophil percentage was correlated with FeNO, ROC curve of these parameters did not show useful values (AUC = 0.297, p = 0.003; AUC = 0.295, p = 0.021).
Blood eosinophils and FeNO can accurately predict eosinophilic airway inflammation in uncontrolled asthmatic patients. FeNO is poor surrogates for sputum neutrophils and blood eosinophils. The FeNO level and blood eosinophils, which determine an optimal cutoff for sputum eosinophilia, need more studies.
呼出一氧化氮分数（FeNO）和血液嗜酸性粒细胞是用于哮喘诊断和管理的嗜酸性气道炎症生物标志物，尽管诱导痰是哮喘表型的金标准检测方法。然而，痰嗜酸性粒细胞、FeNO和血液嗜酸性粒细胞之间相关性的临床应用存在争议。
探讨痰嗜酸性粒细胞、FeNO和血液嗜酸性粒细胞之间的相关性在未控制哮喘患者中的临床应用。同时研究这些生物标志物在支气管可逆性和支气管高反应性（BHR）中的关系。
本研究评估了75例未控制的哮喘患者（症状控制和未来不良结局风险）。所有患者在同一天接受以下检查：FeNO检测、肺功能测定、BHR或支气管扩张剂可逆性检测、诱导痰和采血。嗜酸性气道炎症定义为痰嗜酸性粒细胞≥2.5%或FeNO水平≥32十亿分之一（ppb）。
痰嗜酸性粒细胞百分比与FeNO（r = 0.4556；p < 0.0001）和血液嗜酸性粒细胞百分比（r = 0.3647；p = 0.0013）之间存在显著正相关。痰中性粒细胞百分比与FeNO之间存在显著负相关（r = -0.3653；p = 0.0013）。FeNO与血液嗜酸性粒细胞百分比之间无相关性（p = 0.5801）。ROC曲线分析表明，FeNO在截断点为35.5 ppb时可预测痰嗜酸性粒细胞增多[曲线下面积（AUC）0.707，p = 0.004]（敏感性 = 67.3%，特异性 = 73.9%）。血液嗜酸性粒细胞百分比在截断点为1.5%时也具有较高预测价值，AUC为0.73（p = 0.
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