IL6 and chronic obstructive pulmonary disease: The baseline levels of CXCL8 and IL-6 are associated with the frequency of COPD exacerbations.49,50 During COPD exacerbations, CXCL8 and IL-6 levels are significantly elevated in the airways, compared with the stable phase,51 suggesting that the development of COPD exacerbations is driven by airway inflammation driven, in turn, by these cytokines.