CXCL8 and cystic fibrosis: A recent extensive review by the biomarker Special Interest Working Group of the European Cystic Fibrosis Society–Clinical Trials Network Standardization Committee stated that sputum biomarkers hold promise as a direct measure of inflammation, with NE, IL-8, tumor necrosis factor alpha, and IL-1β showing that validity and responsiveness should be considered as outcome measures in clinical trials.