Department of Clinical Sciences, Lund University, Malmö, Sweden.
Department of Medical Sciences, Clinical Physiology, Uppsala University, Sweden; Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden.
Respir Med. 2021 Nov;188:106621. doi: 10.1016/j.rmed.2021.106621. Epub 2021 Sep 21.
Fractional exhaled nitric oxide (FE) is a marker of type 2 airway inflammation used in clinical practice in asthma. However, reference values are needed to broaden the clinical use of FE and this is within the scope of a newly started Global Lung Function Initiative task force. We aim to study FE levels with special emphasis on the upper limit of normal (ULN) in relation to the type and degree of IgE sensitisation.
FE was measured in 1855 non-smoking, respiratory healthy subjects from the Swedish CArdioPulmonary bioImage Study (SCAPIS). Atopic subjects (n = 424), defined as being IgE-sensitised to aeroallergens (ImmunoCAP Phadiatop™, ≥0.35 PAU/l) were compared to non-atopic subjects (<0.35 PAU/l, n = 1431). Atopic subjects were further characterised according to their grade of IgE sensitisation (IgE antibody tertiles: (T1<1.16, T2 1.16-3.72 and T3 >3.72 PAU/l) and sensitisation to perennial (cat or mite) or seasonal (birch) allergens.
Subjects IgE-sensitised to cat or mite had higher FE compared to non-atopic subjects (FE (ppb): median 20.0 vs. 15.0, and ULN 50.4 vs. 33.0, p < 0.001). This was seen to a lesser extent for subjects IgE-sensitised to birch only (median 18.0 vs. 15.0, and ULN 38.0 vs. 33.0, p = 0.048). Atopic subjects with a high degree of IgE sensitisation (Phadiatop: >3.72 PAU/l) had the highest FE compared to non-atopic subjects (median 20.0 vs. 15.0, and ULN 56.0 vs. 33.0, p < 0.001).
The type and degree of IgE sensitisation should be considered in generating FE reference values.
呼出气一氧化氮分数（FE）是 2 型气道炎症的标志物，在哮喘的临床实践中得到应用。然而，为了拓宽 FE 的临床应用范围，需要参考值，这属于新成立的全球肺功能倡议工作组的范围。我们旨在研究 FE 水平，特别强调与 IgE 致敏类型和程度相关的正常上限（ULN）。
在瑞典心肺生物影像研究（SCAPIS）中，测量了 1855 名不吸烟、呼吸健康的非过敏性受试者的 FE。将过敏性受试者（n=424）定义为对过敏原（ImmunoCAP Phadiatop™，≥0.35 PAU/l）呈 IgE 致敏，与非过敏性受试者（<0.35 PAU/l，n=1431）进行比较。根据 IgE 致敏程度（IgE 抗体三分位：（T1<1.16，T2 1.16-3.72 和 T3 >3.72 PAU/l）和对常年（猫或尘螨）或季节性（桦树）过敏原的致敏情况，进一步对过敏性受试者进行特征描述。
对猫或尘螨过敏的受试者的 FE 高于非过敏性受试者（FE（ppb）：中位数 20.0 比 15.0，ULN 50.4 比 33.0，p<0.001）。对仅对桦树过敏的受试者，这种情况则不那么明显（中位数 18.0 比 15.0，ULN 38.0 比 33.0，p=0.048）。IgE 高度致敏（Phadiatop：>3.72 PAU/l）的过敏性受试者的 FE 高于非过敏性受试者（中位数 20.0 比 15.0，ULN 56.0 比 33.0，p<0.001）。
在生成 FE 参考值时，应考虑 IgE 致敏的类型和程度。
