At baseline, 15 analytes were significantly different between COPD subjects and either smoker or non-smoker controls: adiponectin, β-defensin-2, CRP (C-reactive protein), CCL18 (Chemokine (C-C motif) ligand 18), fibrinogen, hepatocyte growth factor, CXCL10, IL-12p40, IL-6, IL-8, MMP-8, MMP-9, CCL2, myeloperoxidase and prolactin (Table 2). This evidence concerns the gene MMP9 and chronic obstructive pulmonary disease.