Monitoring of Inflammatory Markers in Exhaled Breath Condensate in patients with Asthma and Development of Evaluating System of Asthma Severity

气道炎症的评估对哮喘的诊断和治疗具有重要意义。与支气管肺泡灌洗或支气管活检相比，呼气冷凝（EBC）是一种侵入性较小的方法。测定EBC中的介质可能是监测哮喘气道炎症的有用方法。本研究的目的是建立EBC采集方法，寻找可测量的反映哮喘气道炎症的生物标志物，以及这些生物标志物与哮喘严重程度和肺功能的关系。非吸烟健康受试者58名，无症状吸烟者7名，普通感冒受试者9名，哮喘患者55名，疾病严重程度从轻度间歇性到重度持续性不等。我们测量了EBC中pH、CRP、白蛋白、嗜酸性阳离子蛋白（ECP）、H_2O_2和亚硝酸盐/硝酸盐的水平。哮喘组CRP、H_2O_2、亚硝酸盐/硝酸盐水平均显著高于对照组。在哮喘严重程度上，轻度持续组的pH、CRP、ECP、H_2O_2、硝酸盐水平均显著高于其他严重组。此外，EBC中H_2O_2水平与亚硝酸盐/硝酸盐水平显著相关。FEV1和PEFR与ECO、H_2O_2和亚硝酸盐/硝酸盐水平呈显著负相关。EBC收集是非侵入性的，通过测量哮喘管理中的炎症标志物来评估气道炎症是有用的。

The evaluation of airway inflammation is important for the diagnosis and treatment of asthma. The exhaled breath condensate (EBC) is a less invasive method compared with bronchoalveolar lavage or bronchial biopsy. Measurement of mediators in EBC could be a useful method for monitoring airway inflammation in asthma. The aims of this study are to establish the EBC collection method and to find measurable biomarkers reflecting asthmatic airway inflammation and the relationship between these biomarkers and asthmatic severity and lung function. Fifty-eight non-smoking healthy subjects, 7 asymptomatic smokers, 9 common cold subjects and 55 asthmatics with disease severity ranging from mild intermittent to severe persistent were enrolled. We measured the levels of pH, CRP, albumin, Eosinophil cationic protein (ECP), H_2O_2, and nitrite/nitrate in EBC. The levels of CRP, H_2O_2, nitrite/nitrate of the asthma group were significantly higher than in the control group. In asthmatic severity, the levels of pH, CRP, ECP, H_2O_2 and nitrate in the mild persistent group were significantly higher than the other groups with severity. In addition, the H_2O_2 level in EBC significantly correlated with that of nitrite/nitrate. FEV1 and PEFR showed a significant negative correlation with the levels of ECO, H_2O_2 and nitrite/nitrate. EBC collection is noninvasive and useful to evaluate airway inflammation by measuring inflammatory markers in the management of asthma.