CCL2 and severe acute respiratory syndrome: Earlier researches demonstrated that serum levels of proinflammatory factors IFN-γ, IL1β, IL-6, IL-12, IL-18, IP-10, MCP-1, and CCL2 (CC chemokine ligand-2), CXCL-10 and IL-8 are positively correlated with lung inflammation and extensive lung tissue injury in SARS patients (19–21).