IL33 and Splenomegaly: Analysis of IkkeK38A/K38ATbk1fl/D135NCx3cr1-Crewt/tgIl1.18.33r-/- revealed that combined IL-1R1, IL-18R1 and IL-33R deficiency ameliorated splenomegaly, granulocytosis, and monocytosis, revealing an important role for IL-1, IL-18, and IL-33 in driving systemic inflammation in these animals (Fig. 10a).