IL-8 has previously been identified as an inflammatory biomarker related to systemic inflammation in COPD patients [18], and although their levels are higher at COPD stability compared with controls, the magnitude of the IL-8 increase was even more remarkable during acute exacerbations, mainly in those patients with the FE phenotype [19,20]. The gene discussed is CXCL8; the disease is chronic obstructive pulmonary disease.