Haploidentical Hematopoietic Stem Cell Transplantation Without in Vitro T-cell Depletion for the Treatment of Hematological Malignancies

Many patients who require allogeneic hematopoietic stem cell transplantation (allo-HSCT) lack a human leukocyte antigen (HLA)-matched donor. Here, we report a protocol for haploidentical allo-HSCT that combines granulocyte-colony stimulating factor primed bone marrow (G-BM) and peripheral blood stem cells (PBSC) without in vitro T-cell depletion (TCD). In this study, 171 patients, including 86 in high-risk group, underwent transplantation from haploidentical family donors. All patients achieved sustained, full donor chimerism. One hundred and eleven patients were alive in remission at a median of 682 (253-1502) days. The cumulative incidence of grade III-IV acute graft-versus-host disease (GVHD) was 23% and that of extensive chronic GVHD, 47%; these were not influenced by HLA disparity. Patients younger than 15 years had less grade III-IV acute GVHD than older patients (P=0.044). The 2-year probability of relapse was 12% for standard-risk disease and 39% for high-risk disease. The 2-year probability of leukemia-free survival (LFS) was 68% for standard-risk patients and 42% for high-risk patients (P=0.0009). Grade III-IV acute GVHD was associated with better LFS (P=0.0017). The results require confirmation and show that G-BM combined with PBSC from haploidentical family donors, without in vitro TCD, may be used as a good source of stem cells for allo-HSCT.