In patients with COVID-19 pneumonia, an immune-mediated “cytokine storm” with several pro-inflammatory agents (IL-6, IL-8, IL-1β, granulocyte-macrophage colony-stimulating factor, and reactive oxygen species) and chemokines (such as CCL2, CCL-5, IFNγ-induced protein 10 (IP-10), and CCL3) all contribute to the acute respiratory failure and acute respiratory distress syndrome (ARDS). Here, CCL2 is linked to acute respiratory distress syndrome.