CCL2 and severe acute respiratory syndrome: Several studies showed that seriously ill SARS patients expressed high serum levels of pro-inflammatory cytokines (IFN-γ, IL-1, IL-6, IL-12, and TGFβ) and chemokines (CCL2, CXCL10, CXCL9, and IL-8) compared to uncomplicated SARS patients (Wong et al., 2004; Zhang et al., 2004; Wang et al., 2005; Chien et al., 2006).