Serum levels of interleukin(IL)-18, -13, -4 and interferon (IFN)-γ in chronic obstructive pulmonary disease (COPD) patients, smokers and nonsmokers
| Nonsmoker | Smoker | COPD | |
| Subjects n | 47 | 34 | 62 |
| Serum IL-18 pg·mL−1 | 126.0±10.2 | 205.5±13.6* | 227.6±10.7* |
| Serum IL-13 pg·mL−1 | 23.1±9.4 | 21.4±7.9 | 24.4±10.0 |
| Serum IL-4 pg·mL−1 | 3.0±0.7 | 3.9±1.1 | 3.0±0.6 |
| Serum IFN- γ pg·mL−1 | 1.9±0.7 | 2.0±0.7 | 2.2±0.6 |
Data are presented as mean±sem, unless otherwise stated. *: p<0.05 versus nonsmokers.