MARCO and chronic obstructive pulmonary disease: As compared to NoS, untreated, unchallenged MDMs from COPD-ES subjects demonstrated significantly greater expression of the scavenger receptor MARCO (p = 0.03), CD1d (non-classical MHC, lipid antigen presentation, p = 0.008), CD93 (calcium ion binding, protein and carbohydrate ligand recognition, C1qR complex, p = 0.002) and CD14 (lipoteichoic acid (LTA) and lipopolysaccharide (LPS) ligand recognition, p = 0.02) and approached statistical significance for scavenger receptor SR-AI (p = 0.06) (Figs 1A and S2).