A study in Myd88-/- mice infected with L. major has highlighted the importance of TLRs, IL-1 and/or IL-18 in the induction of IL-12 and the generation of Th1 responses; MyD88 deficiency also resulted in complete abrogation of IFNγ production by CD4+ T cells and an inability to control infection [5]. The gene discussed is IL18; the disease is infection.