Inflammatory Molecular Endotypes in Bronchiectasis: A European Multicenter Cohort Study

Although inflammation and infection are key disease drivers in bronchiectasis, few studies have integrated host inflammatory and microbiome data to guide precision medicine. To identify clusters among patients with bronchiectasis on the basis of inflammatory markers and to assess the association between inflammatory endotypes, microbiome characteristics, and exacerbation risk. Patients with stable bronchiectasis were enrolled at three European centers, and cluster analysis was used to stratify the patients according to the levels of 33 sputum and serum inflammatory markers. Clusters were compared in terms of microbiome composition (16S ribosomal RNA sequencing) and exacerbation risk over a 12-month follow-up. A total of 199 patients were enrolled (109 [54.8%] female; median age, 69 yr). Four clusters of patients were defined according to their inflammatory profiles: cluster 1, milder neutrophilic inflammation; cluster 2, mixed-neutrophilic and type 2; cluster 3, most severe neutrophilic; and cluster 4, mixed-epithelial and type 2. Lower microbiome diversity was associated with more severe inflammatory clusters (