CCL2 and severe acute respiratory syndrome: Pro-inflammatory cytokines (PICs) and chemokines in plasma, such as interleukin (IL)-1, IL-6, IL-12, IL-8, monocyte chemoattractant protein-1 (MCP-1), and interferon-gamma-inducible protein 10 (IP-10), are significantly elevated in the plasma of patients with SARS [40, 41].