Macrophages may be activated by cigarette smoke extract to release inflammatory mediators, including tumour necrosis factor (TNF-) a, IL-8, other CXC chemokines, monocyte chemotactic peptide (MCP)-1, LTB4, and reactive oxygen species providing a cellular mechanism that links smoking with inflammation in COPD. This evidence concerns the gene CXCL8 and chronic obstructive pulmonary disease.