Figure 1.

The airway microbiome in neutrophilic (Neutro) and eosinophilic (Eosino) chronic obstructive pulmonary disease (COPD). (A) The number of sputum samples in Neutro, Eosino, mixed, and paucigranulocytic (Pauci) subgroups across stability and exacerbations in the COPDMAP (COPD Medical Research Council/Association of the British Pharmaceutical Industry), AERIS (Acute Exacerbation and Respiratory Infections in COPD), and BEAT-COPD (Biomarkers to Target Antibiotic and Systemic COPD) cohorts. (B) Shannon diversity of the airway microbiome in sputum samples in the Neutro, Eosino, mixed, and Pauci subgroups. A significantly reduced α diversity was observed for the Neutro subgroup compared with the other groups. (C) Principal coordinate (PC) analysis based on Bray-Curtis dissimilarity for samples in four inflammatory subgroups. The microbiome significantly differed across the four groups (permutational ANOVA, R² = 0.039, P = 0.001). The density plot showed a more diverse PC1 distribution for the Neutro subgroup than for the other groups.