IL4 and COVID-19: The levels of IL-4, IL-13, CCL11 (also known as eotaxin-1), and MCP-4/CCL13 were comparable between HVs and COVID-19 patients with mild/moderate and severe disease but were increased in the subset of COVID-19 patients who died, consistent with a previous report showing an upward trend for IL-4 and IL-13 over the course of the disease in patients with severe COVID-19 (15).