HLA-Haploidentical Hematopoietic Cell Transplantation of Ex Vivo Tcrαβ-Depleted Grafts with CD45RA-Depleted Memory T Cell Add-Back in Adults and Children with Hematological Malignancies: 4-Year Follow-up of Multicenter Study in Singapore

Background: Haploidentical hematopoietic cell transplantation (HCT) provides an alternative option for patients without HLA-matched donors. Graft-versus-host disease (GVHD), engraftment failure, and infectious complications are main causes of non-relapse mortality (NRM). We hypothesized that selective depletion of TCRαβ+ and CD45RA+ naïve T cells will permit hematopoietic engraftment while effectively reducing GVHD and providing donor immune reconstitution through adoptive transfer of donor's mature NK cells, γδ T cells and CD45RO+ memory T cells.