IL6 and chronic obstructive pulmonary disease: In addition, C-reactive protein (CRP), necrosis factor-alpha (TNFα), interleukin-6 (IL-6), pulmonary and activation-regulated chemokine (PARC), vascular endothelial growth factor (VEGF), and tumor matrix metalloproteinase 9 (MMP-9), have been linked to the development of COPD (85).