IL18 and COVID-19: Studies have shown that serum levels of interleukin (IL)-1b, IL-1RA, IL-2, IL-6, IL-7, IL-8, IL-9, IL-10, IL-17, IL-18, tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ) are significantly increased in COVID-19 [9,14,15,16], and some of them (IL-6, IL-8, and TNF-α) are independently correlated with disease severity [4].