Fig. 2From: The association between airway eosinophilic inflammation and IL-33 in stable non-atopic COPDSerum (a) and sputum (b) IL-33 concentrations in healthy non-smokers, healthy smokers and patients with COPD. Comparison of serum (c) and sputum (d) IL-33 between COPD subjects with and without sputum eosinophilia. Data are presented as mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001Back to article page