In agreement with previous studies of haplo-HSCT with PTCy (24), we found that NK cell alloreactivity as predicted by the missing ligand model (donor NK cell benefit) or activating KIR/ligand model (KIR2DS1/C1C2 epitope combination), both of which have been widely investigated in studies of matched unrelated donor HSCT, did not affect outcomes. This evidence concerns the gene KIR3DL1 and pituicytoma.