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. The gene discussed is CXCL8; the disease is chronic obstructive pulmonary disease.