IL18 and COVID-19: The elevated levels of multiple cytokines including IL-1β, IL-2, IL-6, IL-7, IL-8, IL-10, IL-12, IL-17, IL-18, TNF-α, MCP-1, G-CSF, GM-CSF, IP-10, and IFN-γ have been reported in COVID-19 cases with severe symptoms.26