Bayley D L, Abusriwil H, Ahmad A, Stockley R A
Dept of Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TH, UK.
Eur Respir J. 2008 May;31(5):943-8. doi: 10.1183/09031936.00081707. Epub 2008 Jan 23.
The use of exhaled breath condensate (EBC) as a tool for noninvasive assessment of lung inflammation is becoming commonplace. Many authors use commercial ELISA kits to measure inflammatory mediators within EBC. However, the very low concentrations of mediators within EBC are often below the commercially validated concentration range of the relevant ELISA and crucially below the linear part of the sigmoid standard curve. The present study seeks to validate a series of assays for use in EBC and to compare the results in EBC with those from matched sol phase sputum samples. The following mediators were measured by ELISA: leukotriene (LT)B(4), interleukin (IL)-8, secretory leukoprotease inhibitor and alpha(1)-antitrypsin (AAT). Myeloperoxidase was measured by chromogenic substrate assay. Mediator concentrations reached the lower limit of quantification in only one assay (AAT) in 19.6% of subjects, while mediator concentrations reached the lower limit of detection in three assays (LTB(4), IL-8 and AAT in 31, 6.5 and 61% of subjects, respectively). No significant correlations were present between any mediators in EBC and sol phase sputum. The results of the present study indicate that care must be exercised when interpreting mediator measurements in exhaled breath condensate and that assays must be validated at concentrations relevant to those found within the biological fluid.
使用呼出气冷凝物（EBC）作为无创评估肺部炎症的工具正变得越来越普遍。许多作者使用商业酶联免疫吸附测定（ELISA）试剂盒来测量EBC中的炎症介质。然而，EBC中介质的浓度非常低，往往低于相关ELISA商业验证的浓度范围，关键是低于S形标准曲线的线性部分。本研究旨在验证一系列用于EBC的检测方法，并将EBC中的结果与匹配的液相痰液样本的结果进行比较。通过ELISA测量以下介质：白三烯（LT）B4、白细胞介素（IL）-8、分泌型白细胞蛋白酶抑制剂和α1-抗胰蛋白酶（AAT）。通过显色底物法测量髓过氧化物酶。介质浓度仅在19.6%的受试者的一种检测方法（AAT）中达到定量下限，而介质浓度在三种检测方法（LTB4、IL-8和AAT，分别在31%、6.5%和61%的受试者中）达到检测下限。EBC和液相痰液中的任何介质之间均无显著相关性。本研究结果表明，在解释呼出气冷凝物中的介质测量结果时必须谨慎，并且检测方法必须在与生物流体中发现的浓度相关的浓度下进行验证。
