Background

Eosinophils in induced sputum are not only a useful biomarker for diagnosing asthma but are also associated with severe asthma. However, little is known about the association between eosinophils in spontaneous sputum and asthma severity.

Objective

To investigate whether spontaneous sputum eosinophils are related to severe asthma in adult patients with asthma.

Methods

We conducted a retrospective cross-sectional study on 86 people with asthma whose spontaneous sputa were successfully collected. Patients were classified into 4 phenotypes according to the eosinophil and neutrophil levels in spontaneous sputum. We determined the association between inflammatory phenotypes and severe asthma. Moreover, we also compared asthma severity among the phenotypes classified according to blood eosinophils and spontaneous sputum eosinophils.

Results

Asthma phenotypes were as follows: paucigranulocytic, 30.2%; neutrophilic, 18.6%; eosinophilic, 32.6%; and mixed, 18.6%. People with eosinophilic asthma had the highest blood eosinophils, total immunoglobulin E (IgE), and fractional exhaled nitric oxide among the 4 phenotypes. Significant differences were observed in asthma severity between the phenotypes (P = .019). In particular, 57.2% and 56.2% of patients had severe eosinophilic asthma and mixed asthma, respectively. The logistic regression analysis revealed that spontaneous sputum eosinophilia represented the strongest association with severe asthma among the inflammatory variables. Finally, more patients with severe asthma were included in the phenotype with spontaneous sputum eosinophils greater than 3% and blood eosinophils less than or equal to 300/μL and in the phenotype with spontaneous sputum eosinophils greater than 3% and blood eosinophils greater than 300/μL.

Conclusion

Spontaneous sputum can provide helpful information on airway inflammatory phenotyping in patients with asthma.

中文翻译：

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自发性痰区分哮喘患者的炎症表型。

背景

诱导痰中的嗜酸性粒细胞不仅是诊断哮喘的有用生物标志物，而且还与严重哮喘有关。但是，关于自发性痰中嗜酸性粒细胞与哮喘严重程度之间的关系知之甚少。

目的

调查自发痰嗜酸性粒细胞是否与成年哮喘患者的严重哮喘有关。

方法

我们对成功收集了自发性痰液的86例哮喘患者进行了回顾性横断面研究。根据自发痰中的嗜酸性粒细胞和中性粒细胞水平，将患者分为4个表型。我们确定了炎症表型与严重哮喘之间的关联。此外，我们还比较了根据血液嗜酸性粒细胞和自发痰嗜酸性粒细胞分类的表型中哮喘的严重程度。

结果

哮喘的表型如下：Paucigranulocytic，30.2％；中性粒细胞，18.6％; 嗜酸性的，32.6％; 和混合，18.6％。嗜酸性粒细胞性哮喘的人在这四个表型中具有最高的血液嗜酸性粒细胞，总免疫球蛋白E（IgE）和呼出的一氧化氮分数。表型之间哮喘严重程度差异显着（P = .019）。特别是，分别有57.2％和56.2％的患者患有严重的嗜酸性粒细胞性哮喘和混合性哮喘。Logistic回归分析显示，自发性痰嗜酸性粒细胞增多是炎症变量中与严重哮喘的最强关联。最后，更多的重度哮喘患者的表型包括自发性痰嗜酸性粒细胞大于3％，血液中的嗜酸性粒细胞小于或等于300 /μL，表型中的自发性痰嗜酸性粒细胞大于3％和血液嗜酸性粒细胞大于300 /μL。微升

结论

自发性痰可以为哮喘患者的气道炎症表型提供有用的信息。