| Normal | Mild to moderate asthma (GINA 1–3) | Severe asthma (GINA 4–5) | |
| Number | 10 | 15 | 12 |
| Age* | 38 (4) | 48 (4) | 50 (4) |
| Male/female | 4/6 | 8/7 | 6/6 |
| Never/current/ex-smokers | 9/0/1 | 9/0/6 | 10/0/2 |
| Pack years* | 0 (0) | 3 (1) | 3 (2) |
| Atopy, (%) | 5 (50) | 10 (66) | 9 (75) |
| PC20FEV1 (mg/ml)† | >16 | 0.3 (0.1 to | 0.4 (0.1 to |
| FEV1, % predicted* | 98.4 (4.5) | 89.7 (4.9) | 80.2 (6.6) |
| Pre-BD FEV1/FVC, %* | 77.9 (3.3) | 74.4 (2.9) | 74.5 (3.4) |
| BD response (%)* | 1.1 (1.2) | 8.8 (4.1) | 12.5 (5.7) |
| Sputum cell counts | |||
| TCC* | 2.1 (0.6) | 2.9 (0.7) | 2.7 (0.6) |
| Eosinophils, %† | 0.4 (0.1 to 0.8) | 0.9 (0.4 to 2.8) | 2.9 (0.8 to 10.6) |
| Neutrophils, %* | 48.8 (17.7) | 55.2 (7.0) | 59 (9.7) |
| Macrophages, %* | 47.4 (11.7) | 37.1 (6.3) | 25.1 (5.8) |
| Lymphocytes, %* | 1.9 (1.2) | 1.1 (0.2) | 1.5 (0.7) |
| Epithelial cells, %* | 1.4 (1.2) | 4.0 (1.6) | 6.9 (3.3) |
| GM-CSF | |||
| Submucosa‡ | 0 (0.5) | 0 (2.5) | 1.4 (3.0) |
| ASM‡ | 0 (0) | 0 (0) | 0 (0) |
| GM-CSFR | |||
| Submucosa‡ | 0 (1.6) | 1.1 (5) | 2.1 (8.4) |
| ASM‡ | 0 (0.8) | 1.2 (2.2) | 2.4 (5.5) |
*Mean (SE). †Geometric mean (95% CI). ‡Median (interquartile range).
ASM, airway smooth muscle; BD, bronchodilator; FEV1, forced expiratory voume in 1 s; FVC, forced vital capacity; GINA, Global Iniative for Asthma; GM-CSF, granulocyte–macrophage colony-stimulating factor; GM-CSFR, granulocyte–macrophage colony-stimulating factor receptor; PC, provocation concentration; TCC, total cell count.