A Naive Nk Cell Repertoire In The Circulation Of Haploidentical Stem Cell Donors Pre Mobilization Predicts Rejection Of Cord Myeloid Cells In Patients Undergoing Combined Haploidentical And Unrelated Cord Blood Hsct

Background: For patients (pts) with severe aplastic anemia (SAA) lacking an HLA identical donor, outcomes of hematopoietic stem cell transplantation (HSCT) using unrelated cord blood (UCB) units or haplo-identical donors (HDs) have historically been associated with high graft failure rates and poor survival. In an ongoing clinical trial at the NHLBI, we have observed excellent engraftment (100%) and survival (91%) in SAA pts (n=27) receiving a transplant that co-infuses a single UCB unit with CD34-selectedCD3-depletedcells from a haplo-identical relative. Although cord myeloid engraftment(defined as cord ANC >500/μL) occurred atday 100) or no cord myeloid engraftment. In this analysis, we investigated factors that may have impeded cord myeloid engraftment following UCB/HD transplantation.