CXCL8 and chronic obstructive pulmonary disease: Indeed, COPD patients show persistent low-grade systemic inflammation as shown by elevated levels of circulating leukocytes, C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α) and fibrinogen [7], [8].