IL18 and COVID-19: In COVID-19, upon entering cells via the surface protein angiotensin-converting enzyme 2 (ACE2), viral-derived dsRNA and ssRNA can be sensed by TLR3, TLR7 and melanoma differentiation-associated protein 5 (MDA5), which via NF-κB upregulate pro-IL-1β and pro-IL-18 that are later cleaved into their active forms by fully activated NLRP3 (Figure 1).