The airway microbiome in patients with severe asthma: Associations with disease features and severity

Background Asthma is heterogeneous, and airway dysbiosis is associated with clinical features in patients with mild-to-moderate asthma. Whether similar relationships exist among patients with severe asthma is unknown. Objective We sought to evaluate relationships between the bronchial microbiome and features of severe asthma. Methods Bronchial brushings from 40 participants in the Bronchoscopic Exploratory Research Study of Biomarkers in Corticosteroid-refractory Asthma (BOBCAT) study were evaluated by using 16S ribosomal RNA–based methods. Relationships to clinical and inflammatory features were analyzed among microbiome-profiled subjects. Secondarily, bacterial compositional profiles were compared between patients with severe asthma and previously studied healthy control subjects (n = 7) and patients with mild-to-moderate asthma (n = 41). Results In patients with severe asthma, bronchial bacterial composition was associated with several disease-related features, including body mass index ( P