Description of the study participants and the number of samples per group and per sampling site
| Non-COPD controls | COPD | ||||
| GOLD 1 | GOLD 2 | GOLD 3 | GOLD 4 | ||
| Participants | 10 | 6 | 8 | 8 | 10 |
| Male | 5 (50.0%) | 3 (50.0%) | 7 (87.5%) | 4 (50.0%) | 8 (80.0%) |
| Age years mean | 58.3 | 68.7 | 66.9 | 66.0 | 62.6 |
| Smoking status | |||||
| Nonsmoker | 3 (30.0%) | 2 (33.3%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
| Ex-smoker | 2 (20.0%) | 2 (33.3%) | 4 (50.0%) | 5 (62.5%) | 9 (90.0%) |
| Active smoker | 5 (50.0%) | 2 (33.3%) | 4 (50.0%) | 3 (37.5%) | 1 (10.0%) |
| FEV1# % predicted | 95.0±8.5 | 86.0±4.6 | 68.3±9.2 | 36.3±5.1 | 25.2±4.4 |
| Annual exacerbation rate | 0.0±0.0 | 0.0±0.0 | 0.5±0.7 | 1.4±0.7 | 1.2±1.2 |
| mMRC score | 1.0±1.4 | 1.2±1.1 | 0.9±0.8 | 3.3±1.4 | 3.1±1.2 |
| CAT score | 7.5±0.7 | 7.4±5.4 | 8.6±3.6 | 19.6±5.5 | 17.3±6.9 |
| COPD medication | |||||
| LABA | 0 (0.0%) | 0 (0.0%) | 2 (25.0%) | 1 (12.5%) | 2 (20.0%) |
| LAMA | 0 (0.0%) | 1 (16.7%) | 6 (75.0%) | 6 (75.0%) | 7 (70.0%) |
| ICS | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
| LABA+ICS | 2 (20.0%) | 2 (33.3%) | 3 (37.5%) | 7 (87.5%) | 9 (90.0%) |
| LABA+LAMA | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 1 (12.5%) | 1 (10.0%) |
| PDE-4 inhibitor | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 1 (12.5%) | 0 (0.0%) |
| Theophylline | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 2 (25.0%) | 0 (0.0%) |
| Total number of samples | 62 | 41 | 38 | 19 | 27 |
| BAL samples for microbiota/gene expression analysis | 10/10 | 6/6 | 7/6 | 3/8 | 4/9 |
| Lingula | 3 | 2 | 2 | 0 | 1 |
| Lower lobe | 8 | 5 | 3 | 2 | 2 |
| Main bronchus | 9 | 7 | 4 | 2 | 3 |
| Pharynx | 10 | 6 | 7 | 8 | 10 |
| Trachea | 9 | 6 | 7 | 2 | 4 |
| Upper lobe | 9 | 6 | 5 | 2 | 2 |
| Middle lobe | 4 | 3 | 3 | 0 | 1 |
Data are presented as mean±sd unless otherwise stated. COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease; FEV1: forced expiratory volume in 1 s; mMRC: modified Medical Research Council dyspnoea scale; CAT: COPD Assessment Test; LABA: long-acting β2-agonist; LAMA: long-acting muscarinic antagonist; ICS: inhaled corticosteroid; PDE: phosphodiesterase; BAL: bronchoalveolar lavage. #: post-bronchodilatation.