In healthy volunteers (Figure 5), or individuals with COPD and their age matched controls (Figure 6), MDMs differentiated in the presence of low concentrations of DEP produced markedly less CXCL8 in response to LPS (TLR4) and gardiquimod (TLR7), but similar levels in response to Pam3CSK4 (TLR2) and TNFα. This evidence concerns the gene TLR4 and chronic obstructive pulmonary disease.