In addition, a variety of pro-inflammatory cytokines have also been demonstrated to delay neutrophil apoptosis in vitro; these include e.g. granulocyte macrophage-colony stimulating factor (GM-CSF) and IL-8, both of which have been shown to be increased in the airways of subjects with COPD and in our mice exposed to CS [1]. This evidence concerns the gene CXCL8 and chronic obstructive pulmonary disease.