CCL2 and infection: Cytokine storm syndrome (CSS) refers to the continuous activation and expansion of lymphocytes and macrophages caused by the infection of microorganisms, and a variety of cytokines such as TNF-α, IL-1, IL-6, IL-12, interferon (IFN)-α, IFN-β, IFN-γ, monocyte chemoattractant protein (MCP)-1, and IL-8 are rapidly produced in large quantities (57).