IL18 and viral infectious disease: In particular, IL-20/IL20RA-mediated signaling greatly increases the expression of several genes, that is, 2'−5'-oligoadenylate synthetase (Oas1a and Oas1g) and Il18, involved in OAS-RNase L-mediated NOD-like receptor (NLR) signaling pathway (Figure 7—figure supplement 1B, C), which regulates inflammasome signaling to activate Caspase-1 and hence the production of functional inflammatory cytokines IL-1β and IL-18 by cleavage during viral infections (Banerjee, 2016; Chakrabarti et al., 2015).