| Normal | Mild asthma (GINA 1) | Moderate asthma (GINA 2–4) | Severe asthma (GINA 5) | GOLD II | GOLD III | GOLD IV | |
| Number | 18 | 13 | 14 | 18 | 16 | 17 | 14 |
| Age* | 54 (3) | 53 (4) | 51 (4) | 49 (5) | 71 (2) | 68 (2) | 72 (11) |
| Male/female | 4/14 | 8/5 | 4/10 | 7/11 | 9/7 | 12/5 | 13/1 |
| Never/current/ex-smokers | 9/0/9 | 11/0/11 | 10/0/4 | 16/0/2 | 2/9/5 | 0/6/11 | 0/4/10 |
| Pack-years* | 17 (5) | 2 (1) | 6 (3) | 4 (3) | 43 (8) | 52 (4) | 56 (9) |
| Atopy, n (%) | 6 (33) | 7 (54) | 11 (79) | 13 (72) | 7 (44) | 7 (41) | 5 (36) |
| PC20FEV1 (mg/ml)† | >16 | 1 (0.3 to 4.2) | 0.4 (0.1 to 1.5) | 0.1 (0 to 1.6) | – | – | – |
| FEV1, % predicted* | 98.7 (3.0) | 80.4 (5.1) | 66.4 (4.4) | 56.4 (6.8) | 60.1 (1.5) | 39.9 (1.3) | 24.1 (1.3) |
| Pre-BD FEV1/FVC, %* | 77.6 (1.7) | 72.1 (3.6) | 67.5 (3.0) | 69.7 (2.8) | 59.4 (2.2) | 50.9 (2.1) | 40.3 (2.0) |
| BD response (%)* | 1.5 (0.7) | 6.0 (3.6) | 5.0 (4.6) | 9.6 (2.0) | 4.3 (2.2) | 6.0 (1.8) | 4.1 (3.2) |
| Sputum cell counts | |||||||
| TCC* | 3.8 (0.9) | 2.34 (0.82) | 3.31 (1.8) | 6.57 (3.3) | 3.3 (0.6) | 4.3 (0.9) | 11.2 (3.2) |
| Eosinophils, %† | 0.5 (0.3 to 0.8) | 2.3 (0.6 to 7.9) | 2.7 (1.0 to 7.3) | 3.8 (1.8 to 8.0) | 2.3 (1.7 to 6.3) | 2.6 (1.4 to 4.7) | 1.0 (0.4 to 2.3) |
| Neutrophils, %* | 55.8 (6.0) | 67.3 (6.9) | 57.8 (5.9) | 64.3 (6.0) | 72.2 (5.0) | 71.0 (4.3) | 85.6 (2.9) |
| Macrophages, %* | 38.5 (5.3) | 20.6 (4.6) | 21.4 (4.7) | 19.2 (4.9) | 29.2 (4.6) | 21.3 (3.3) | 8.7 (1.7) |
| Lymphocytes, %* | 0.4 (1.4) | 0.5 (0.2) | 0.4 (0.1) | 1.9 (1.5) | 1.6 (1.1) | 0.6 (0.2) | 1.0 (0.3) |
| Epithelial cells, %* | 3.7 (1.4) | 3.7 (1.8) | 3.6 (1.7) | 3.3 (1.6) | 3.3 (0.6) | 4.3 (0.9) | 11.2 (3.2) |
*Mean (SE). †Geometric mean (95% CI).
BD, bronchodilator; FEV1, forced expiratory voume in 1 s; FVC, forced vital capacity; GINA, Global Initiative for Asthma; GOLD, Global Initiative for Chronic Obstructive Lung Disease; PC, provocation concentration; TCC, total cell count.