A study of 17 pediatric patients with high risk hematologic malignancies using a RIC conditioning with total lymphoid irradiation (TLI) but without TBI or serotherapy, administered a CD34+ selected PBSC product on day 0, followed by a CD45RA-depleted PBSC product which had been collected the following day, and ultimately a donor NK cell product administered on day +6 with the use of Sirolimus or MMF post-transplant. The gene discussed is CD34; the disease is hematologic disorder.