Pizzichini E, Pizzichini M M, Efthimiadis A, Dolovich J, Hargreave F E
Department of Medicine, St. Joseph's Hospital, Hamilton, Ontario, Canada.
J Allergy Clin Immunol. 1997 Apr;99(4):539-44. doi: 10.1016/s0091-6749(97)70082-4.
Airway eosinophilic inflammation is a characteristic feature of asthma. This can be assessed directly by measurement of eosinophils and eosinophilic cationic protein (ECP) in sputum or indirectly by measurement of the same markers in blood. We investigated the performance of these markers of airway eosinophilic inflammation in a population of patients with asthma compared with control subjects and the extent to which the markers differed.
In a cross-sectional study, subject characteristics were documented on day 1 and induced sputum and blood samples were obtained on day 2. Nineteen patients with asthma and 20 control subjects (10 healthy subjects and 10 smokers with nonobstructive bronchitis) were consecutively enrolled in the study. Sputum (selected from saliva) and blood samples were processed by persons blind to the clinical details. Results are presented as median values (minimum-maximum); differences were measured by Mann-Whitney U test. The accuracy of the tests (sensitivity and specificity) was measured by plotting the data in receiver-operating characteristic (ROC) curves and comparing the areas under the curve for each marker.
Patients with asthma in comparison with control subjects had a higher proportion of sputum eosinophils (5.2% [0.2% to 93%] vs 0.3% [0% to 1.7%], p < 0.001), higher numbers of blood eosinophils (350.0 x 10(6)/L [144.0 to 1520.0 x 10(6)/L] vs 155.0 x 10(6)/L [34.0 to 426.0 x 10(6)/L], p = 0.003), and higher levels of ECP in sputum (1040.0 micrograms/L [76.8 to 32,000.0 micrograms/L] vs 455.3 micrograms/L [54.4 to 1280.0 micrograms/L], p = 0.001) but not in serum (25.0 micrograms/L [5.6 to 52.4 micrograms/L] vs 16.5 micrograms/L [3.3 to 36.0 micrograms/L], p = 0.08). Markers of airway inflammation in induced sputum and blood samples were correlated with clinical and physiologic variables. The area under the ROC curve showed that eosinophils in sputum (0.90) are significantly more accurate markers than blood eosinophils (0.72) and serum ECP (0.67) (p = 0.02). Although the area under the ROC curve for sputum ECP was greater than those for blood eosinophils and serum ECP, the differences could have occurred by chance (p > or = 0.1).
We conclude that the proportion of eosinophils in sputum is a more accurate marker of asthmatic airway inflammation than the proportions of blood eosinophils or serum ECP.
气道嗜酸性粒细胞炎症是哮喘的一个特征性表现。这可以通过检测痰液中的嗜酸性粒细胞和嗜酸性阳离子蛋白（ECP）直接评估，或者通过检测血液中的相同标志物间接评估。我们研究了这些气道嗜酸性粒细胞炎症标志物在哮喘患者群体中的表现，并与对照组进行比较，以及这些标志物的差异程度。
在一项横断面研究中，第1天记录受试者特征，第2天采集诱导痰液和血液样本。19例哮喘患者和20名对照者（10名健康受试者和10名患有非阻塞性支气管炎的吸烟者）连续纳入研究。痰液（从唾液中选取）和血液样本由对临床细节不知情的人员处理。结果以中位数（最小值 - 最大值）表示；差异通过曼 - 惠特尼U检验测量。通过绘制受试者工作特征（ROC）曲线中的数据并比较每个标志物的曲线下面积来测量检测的准确性（敏感性和特异性）。
与对照者相比，哮喘患者痰液嗜酸性粒细胞比例更高（5.2% [0.2%至93%] 对0.3% [0%至1.7%]，p < 0.001），血液嗜酸性粒细胞数量更多（350.0×10⁶/L [144.0至1520.0×10⁶/L] 对155.0×10⁶/L [34.0至426.0×10⁶/L]，p = 0.003），痰液中ECP水平更高（1040.0μg/L [76.8至32,000.0μg/L] 对455.3μg/L [54.4至1280.0μg/L]，p = 0.001），但血清中无差异（25.0μg/L [5.6至52.4μg/L] 对16.5μg/L [3.3至36.0μg/L]，p = 0.08）。诱导痰液和血液样本中的气道炎症标志物与临床和生理变量相关。ROC曲线下面积显示，痰液中的嗜酸性粒细胞（0.90）作为标志物比血液嗜酸性粒细胞（0.72）和血清ECP（0.67）更准确（p = 0.02）。尽管痰液ECP的ROC曲线下面积大于血液嗜酸性粒细胞和血清ECP，但差异可能是偶然发生的（p≥0.1）。
我们得出结论，痰液中嗜酸性粒细胞比例是比血液嗜酸性粒细胞比例或血清ECP更准确的哮喘气道炎症标志物。
