Chest Department, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium; Chest Department, Centre Hospitalier Régional de Namur, Namur, Belgium.
Chest Department, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium.
J Allergy Clin Immunol. 2014 Sep;134(3):554-9. doi: 10.1016/j.jaci.2013.12.1070. Epub 2014 Feb 9.
The increased fraction of exhaled nitric oxide (Feno) values observed in asthmatic patients are thought to reflect increased airway inflammation. However, Feno values can be affected by airway caliber reduction, representing a bias when using Feno values to assess asthma control.
We sought to determine the effect of changes in both airway caliber and inflammation on Feno values using the allergen challenge model.
FEV1 and Feno values were measured during early airway responses (EARs) and late airway responses after challenge with house dust mite allergens in 15 patients with mild allergic asthma. Helium and sulfur hexafluoride (SF6) phase III expired concentration slopes (SHe and SSF6, respectively) from single-breath washout tests were measured to identify sites of airway constriction.
In EARs, FEV1 and Feno value decreases reached 36.8% and 22%, respectively (P < .001). ΔSHe was greater than ΔSSF6 (+189.4% vs +82.2%, P = .001). In late airway responses FEV1 and Feno value decreases reached 31.7% and 28.7%, respectively (P < .001), with the same ΔSHe and ΔSSF6 pattern (+155.8% vs +76%, P = .001). Eight hours after the EAR, FEV1 was still decreased (P < .001), whereas Feno values had returned to baseline. At 24 hours, FEV1 had returned to baseline, with Feno values increased by 38.7% (P = .04).
In patients with mild allergic asthma, airway caliber changes modulate changes in Feno values resulting from airway inflammation. Therefore Feno should no longer be considered solely an inflammation biomarker but rather a biomarker that integrates both airway inflammation and lung function changes. Furthermore, early and late phases resulting from allergen exposure were shown to involve similar lung regions.
哮喘患者呼出的一氧化氮（Feno）分数增加被认为反映了气道炎症的增加。然而，Feno 值可能会受到气道口径缩小的影响，这在使用 Feno 值评估哮喘控制时会产生偏差。
我们旨在使用变应原激发模型确定气道口径和炎症变化对 Feno 值的影响。
在 15 例轻度过敏性哮喘患者中，测量了屋尘螨变应原激发后早期气道反应（EAR）和晚期气道反应期间的 FEV1 和 Feno 值。通过单口气道清除试验测量氦气和六氟化硫（SF6）第三相呼出浓度斜率（分别为 SHe 和 SSF6），以确定气道收缩的部位。
在 EAR 中，FEV1 和 Feno 值下降分别达到 36.8%和 22%（P<0.001）。ΔSHe 大于 ΔSSF6（+189.4%比+82.2%，P=0.001）。在晚期气道反应中，FEV1 和 Feno 值下降分别达到 31.7%和 28.7%（P<0.001），具有相同的ΔSHe 和 ΔSSF6 模式（+155.8%比+76%，P=0.001）。EAR 后 8 小时，FEV1 仍下降（P<0.001），而 Feno 值已恢复到基线。24 小时时，FEV1 已恢复到基线，Feno 值增加了 38.7%（P=0.04）。
在轻度过敏性哮喘患者中，气道口径的变化调节了气道炎症引起的 Feno 值变化。因此，Feno 不应再被视为单纯的炎症生物标志物，而应是一个整合气道炎症和肺功能变化的生物标志物。此外，过敏原暴露引起的早期和晚期阶段显示涉及相似的肺区。
