The nested case-control study (n=98) identified the chemokines chemokine (C-C motif) ligand (CCL)20, CCL27, and chemokine (CX-C motif) ligand (CXCL)13 as putative, plausibly homeostatic biomarkers for biomass smoke-induced COPD. The gene discussed is CCL20; the disease is chronic obstructive pulmonary disease.