CXCL8 and chronic obstructive pulmonary disease: IL-1 and CXCL8/IL-8, neutrophil elastase (NE), matrix metalloproteinase (MMP), myeloperoxidase (MPO), neutrophil extracellular traps (NETs) and high mobility group box 1 (HMGB1) are all shown to be associated with the severity and frequency of COPD [20–23].