Indeed, recent studies suggest that, in addition to their role in the innate immune response to infection and cancer, KIR-HLA (and particularly KIR-C1/C2) interactions control a proper formation of placenta (Chazara et al., 2011; Colucci et al., 2011; Parham et al., 2012b). This evidence concerns the gene KIR3DL1 and infection.