Indeed, while IL-1R−/− mice are highly susceptible to GAS infection and succumb to bacteremia (43), implying that IL-1β (and/or IL-1α) is important to inhibit bacterial outgrowth, it has also been shown that in a panel of mouse strains, increased susceptibility to GAS infection links genetically to a locus on chromosome 2 (Chr2) harboring genes of the IL-1 network and correlates with increased levels of IL-1β and bacterial expansion in infected animals (44). This evidence concerns the gene IL1R1 and bacterial infectious disease with sepsis.