Rosi E, Ronchi M C, Grazzini M, Duranti R, Scano G
Section of Respiratory Medicine, Institute of Internal Medicine and Immunoallergology, University of Florence, Firenze, Italy.
J Allergy Clin Immunol. 1999 Feb;103(2 Pt 1):232-7. doi: 10.1016/s0091-6749(99)70496-3.
Recent studies have shown weak associations among FEV1, bronchial hyperresponsiveness (BHR), sputum eosinophils, and sputum eosinophil cationic protein (ECP), suggesting that they are nonoverlapping quantities. The statistical method of factor analysis enables reduction of many parameters that characterize the disease to a few independent factors, with each factor grouping associated parameters.
The purpose of this study was to demonstrate, by using factor analysis, that reversible airway obstruction, BHR, and eosinophilic inflammation of the bronchial tree, as assessed by cytologic and biochemical analysis of sputum, may be considered separate dimensions that characterize chronic bronchial asthma.
Ninety-nine clinically stable patients with a previous diagnosis of asthma underwent spirometry, sputum induction, and histamine inhalation tests.
Most patients were nonobstructed (FEV1, 91% +/- 20%); a low level of bronchial reversibility (FEV1 increase after beta2 -agonist, 7.8% +/- 9.2%) and BHR (histamine PC20 FEV1 geometric mean, 0.98 mg/mL) were found. Sputum eosinophil differential count (12.4% +/- 17.7%) and sputum ECP (1305 +/- 3072 microg/mL) were in the normal range of our laboratory in 38 and 22 patients, respectively. Factor analysis selected 3 different factors, explaining 74.8% of variability. Measurements of airway function and age loaded on factor I, PC20 FEV1 and beta2 -response loaded on factor II, and sputum ECP and eosinophils loaded on factor III. Additional post hoc factor analyses provided similar results when the sample was divided into 2 subgroups by randomization, presence of airway obstruction, degree of BHR, percentage of sputum eosinophils, or concentration of sputum ECP.
We conclude that airway function, baseline BHR, and airway inflammation may be considered separate dimensions in the description of chronic asthma. Such evidence supports the utility of routine measurement of all these dimensions.
近期研究表明，第一秒用力呼气容积（FEV1）、支气管高反应性（BHR）、痰液嗜酸性粒细胞及痰液嗜酸性粒细胞阳离子蛋白（ECP）之间存在微弱关联，提示它们并非重叠的指标。因子分析的统计方法能够将表征该疾病的众多参数简化为少数几个独立因子，每个因子将相关参数归为一组。
本研究旨在通过因子分析证明，通过痰液的细胞学和生化分析评估的可逆性气道阻塞、BHR以及支气管树的嗜酸性粒细胞炎症，可被视为表征慢性支气管哮喘的不同维度。
99例既往诊断为哮喘且病情临床稳定的患者接受了肺功能测定、痰液诱导及组胺吸入试验。
大多数患者无气道阻塞（FEV1，91%±20%）；支气管可逆性水平较低（β2受体激动剂后FEV1增加，7.8%±9.2%），且存在BHR（组胺PC20 FEV1几何平均值，0.98mg/mL）。痰液嗜酸性粒细胞分类计数（12.4%±17.7%）和痰液ECP（1305±3072μg/mL）在我们实验室中，分别有38例和22例患者处于正常范围。因子分析选择了3个不同因子，解释了74.8%的变异性。气道功能测量值和年龄加载于因子I，PC20 FEV1和β2反应加载于因子II，痰液ECP和嗜酸性粒细胞加载于因子III。当按随机化、气道阻塞情况、BHR程度、痰液嗜酸性粒细胞百分比或痰液ECP浓度将样本分为2个亚组时，额外的事后因子分析提供了类似结果。
我们得出结论，在描述慢性哮喘时，气道功能、基线BHR和气道炎症可被视为不同维度。此类证据支持对所有这些维度进行常规测量的实用性。
