CXCL8 and influenza: Interleukin-6 (IL-6), IL-8, and tumor necrosis factor-α (TNF-α) are potential biomarkers for influenza infection because elevated levels of these pro-inflammatory cytokines in both bronchial epithelial cells and clinical patients' nasopharyngeal lavage fluid correlates with viral loads and scores of typical influenza symptoms7–10.