During the acute phase of infection, plasma viral titers have been shown to correlate with a rapid systemic increase of multiple cytokines (interferon-α (IFN-α), IFN-β, inducible protein 10 (IP-10), tumor necrosis factor (TNF), monocyte chemotactic protein 1 (MCP-1) interleukin-6 (IL-6), IL-8, IL-10, IL-15 and IL-18) in the first 25 days post-infection [6]. The gene discussed is IL15; the disease is infection.