CCL2 and acute respiratory distress syndrome: The levels of proinflammatory cytokines and chemokines including interleukin IL-1β, IL-6, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), inducible protein 10 (IP-10), caspase-1 and monocyte chemotactic protein 1(MCP-1) were high in both circulatory system and bronchoalveolar lavage fluid of COVID-19 ARDS patients (1, 23).