Inflammatory Endotype Associated Airway Microbiome in COPD Clinical Stability and Exacerbations - A Multi-Cohort Longitudinal Analysis

Rationale Understanding the role of airway microbiome in chronic obstructive pulmonary disease (COPD) inflammatory endotypes may help to develop microbiome-based diagnostic and therapeutic approaches. Objectives To understand the association of airway microbiome with neutrophilic and eosinophilic COPD at stability and exacerbations. Methods An integrative analysis was performed on 1,706 sputum samples collected longitudinally from 510 COPD patients recruited at four UK sites in BEAT-COPD, COPDMAP and AERIS cohorts. The microbiome was analyzed using COPDMAP and AERIS as discovery dataset and BEAT-COPD as validation dataset. Results The airway microbiome in neutrophilic COPD was heterogeneous with two primary community types differentiated by the predominance of Haemophilus. The Haemophilus-predominant subgroup had elevated sputum IL-1b and TNFa and was relatively stable over time. The other neutrophilic subgroup with a balanced microbiome profile had elevated sputum and serum IL-17A and was temporally dynamic. Patients in this state at stability were susceptible to greatest microbiome shifts during exacerbations. This subgroup can temporally switch to both neutrophilic-Haemophilus-predominant and eosinophilic states which were otherwise mutually exclusive. Time-series analysis on the microbiome showed the temporal trajectories of Campylobacter and Granulicatella were indicative of intra-patient switches from neutrophilic to eosinophilic inflammation, and in track with patient sputum eosinophilia over time. Network analysis revealed distinct host-microbiome interaction patterns between neutrophilic-Haemophilus-predominant, neutrophilic-balanced-microbiome and eosinophilic subgroups. Conclusions The airway microbiome can stratify neutrophilic COPD into subgroups that justify different therapies. Neutrophilic and eosinophilic COPD are inter-changeable in some patients. Monitoring temporal variability of the airway microbiome may track patient inflammatory status over time.