KIR3DL1 and acute graft versus host disease: No effect of any of the tested KIR-HLA definitions was noted on severe (grade II-IV) acute GVHD, which could be due to the predominant influence of in vivo T cell depletion using ATG on early than late post-transplant events and variability in reconstitution of mature NK cell receptor repertoire after HCT [57–59].