LTB4, CXCL8, MMP9, and TNFα play important roles in COPD inflammation, with CXCL8 and LTB4 acting as neutrophil chemoattractants, TNFα causing amplification of inflammation, and MMP-9 being a protease that can target lung elastin [10]. This evidence concerns the gene MMP9 and chronic obstructive pulmonary disease.