Another study showed that a highly virulent H5N1 virus induced antiviral (IFN-α and IFN-β) and proinflammatory (IL-4, IL-6, IL-8, and IL-15) cytokine mRNA expression in the lung at 24 h post infection, which abruptly decreased within the next 8 h [39]. Here, CXCL8 is linked to infection.