In vitro studies have shown that the pro-inflammatory cytokines GM-CSF, IL-8 and IL-6 inhibit apoptosis of granulocytes [38-41] and therefore the observed increase in IL-6 and IL-8 in COPD subjects compared to non-smokers may account for the reduced neutrophil apoptosis in COPD subjects. This evidence concerns the gene CXCL8 and chronic obstructive pulmonary disease.