Figure 3From: Compartment differences of inflammatory activity in chronic obstructive pulmonary diseaseRelationship between sputum soluble TNFRs and sputum biomarkers. Relationship between sputum concentration of soluble TNF- α receptors and IL-6 and (a, c) and IL-8 (b, d) in healthy non-smokers. Relationship between sputum concentration of sTNFR2 and IL-6 and (e) and IL-8 (f) in smokers with COPD. Rho indicates coefficient of correlation according to Spearman.Back to article page