CCL2 and COVID-19: COVID-19 relevant inflammatory cytokines like interleukin (IL)-6, IL-8, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1) or IL-1β, and anti-inflammatory cytokines like IL-10 or IL-1 receptor antagonist (IL-1ra) were shown to correlate with disease severity (5–8).