CCL2 and acute respiratory distress syndrome: Several studies report elevated levels of pro-inflammatory cytokines and chemokines [i.e., interleukin (IL)-1β, IL-6, IL-8, IL-12, tumor necrosis factor α (TNF-α), interferon γ (IFN-γ), CXCL9, CXCL10, CCL2, CCL3, CCL5, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon-γ inducible protein 10 kD (IP-10)] associated with the development of ARDS in both SARS and MERS patients (Perlman and Netland, 2009; Totura and Baric, 2012; Channappanavar and Perlman, 2017).