CASP4 and serum lipopolysaccharide activity: TLR4 had been considered a gatekeeper of LPS-induced lethality (endotoxemia) and E. coli-induced septic shock, but the non-canonical inflammasome, mediated by caspase-11 in mice or caspase-4/5 in humans, is newly defined as the gatekeeper for the sepsis19.