While IL-18 is known to exert proinflammatory effects such as increased neutrophil phagocytosis and production of reactive oxygen species, paradoxically, IL-18-null (IL-18−/−) neonatal mice demonstrated markedly improved survival and reduced bacteremia in comparison to wild-type neonatal mice when challenged with polymicrobial sepsis (59). Here, IL18 is linked to bacterial infectious disease with sepsis.