IL1RL1 and infection: One study using a blood-stage PbA model of infection on C57BL/6 mice found that administration of IL-33 attenuated the development of experimental cerebral malaria, with its therapeutic effect being attributed to induction of M2 polarization, reduction of inflammatory mediators and expansion of CD45+ST2+ICOS+ ILC2s and Tregs (Besnard et al., 2015).