ProAR, Núcleo de Excelência Em Asma, Universidade Federal da Bahia, Brazil.
Departamento de Clínica Médica, Faculdade de Medicina de Jundiaí, Brazil.
Respir Med. 2018 Dec;145:95-100. doi: 10.1016/j.rmed.2018.10.025. Epub 2018 Oct 23.
Asthma is a syndrome with multiple phenotypes. Peripheral blood eosinophil counts might be the ideal biomarker to identify subjects with eosinophilic asthma. It is available, inexpensive, and it is associated with eosinophilia in sputum.
The aim of this study was to evaluate whether blood eosinophilia is associated with asthma severity and to evaluate whether blood eosinophilia is associated with lack of control of asthma symptoms and airway obstruction.
Case control study. The cases were subjects recruited from a cohort of patients with severe asthma, in Salvador-BR, demanding continuous inhaled corticosteroids and LABA. There were two control groups: 1) subjects with mild/moderate asthma, 2) subjects with no asthma. Subjects enrolled in the study answered questionnaires, had their blood and stool samples collected, performed spirometry and SPT. We established a cutoff ≥ 260 cells/mm3 for blood eosinophilia.
We evaluated 544 subjects in the case group, 452 subjects with mild to moderate asthma and 450 subjects with no asthma. The subjects of the case group had higher odds of presenting the eosinophilic phenotype in comparison to subjects with mild to moderate asthma [OR 1.60 95CI(1.19-2.16)] and no asthma [OR 3.93; 95CI(2.90-5.33)]. The eosinophilic phenotype, according to blood count, is associated with uncontrolled asthma [OR 1.56; 95CI(1.06-2.28)], but it is not associated with airway obstruction [OR 0.87; 95CI(0.61-1.24)].
We conclude that the blood eosinophilia is a biomarker associated with asthma severity and poor symptom control, but we found no association with reduced lung function.
哮喘是一种具有多种表型的综合征。外周血嗜酸性粒细胞计数可能是识别嗜酸性哮喘患者的理想生物标志物。它是可用的、廉价的，并且与痰中的嗜酸性粒细胞增多有关。
本研究旨在评估血液嗜酸性粒细胞是否与哮喘严重程度相关，并评估血液嗜酸性粒细胞是否与哮喘症状控制不佳和气道阻塞有关。
病例对照研究。病例是从萨尔瓦多-巴西的严重哮喘队列中招募的患者，他们需要持续吸入皮质类固醇和 LABA。有两个对照组：1）轻度/中度哮喘患者，2）无哮喘患者。纳入研究的患者回答问卷，采集血液和粪便样本，进行肺功能检查和 SPT。我们设定血液嗜酸性粒细胞≥260 个/毫米 3 作为嗜酸性粒细胞增多的截断值。
我们评估了病例组的 544 名患者、452 名轻度至中度哮喘患者和 450 名无哮喘患者。与轻度至中度哮喘患者相比，病例组患者出现嗜酸性粒细胞表型的可能性更高[比值比 1.60，95%置信区间（1.19-2.16）]，与无哮喘患者相比[比值比 3.93；95%置信区间（2.90-5.33）]。根据血液计数，嗜酸性粒细胞表型与未控制的哮喘相关[比值比 1.56；95%置信区间（1.06-2.28）]，但与气道阻塞无关[比值比 0.87；95%置信区间（0.61-1.24）]。
我们得出结论，血液嗜酸性粒细胞是与哮喘严重程度和症状控制不佳相关的生物标志物，但与肺功能降低无关。
