Haploidentical hematopoietic stem cell transplantation: state of art

For patients with hematologic malignancies at high risk of relapse who do not have matched donors, a suitable alternative stem cell source is the HLA-haploidentical 2- or 3-loci mismatched family donor who is readily available for nearly all patients. Transplantation across the major HLA barrier is associated with strong T-cell alloreactions, which were originally manifested as a high incidence of severe GVHD and graft rejection. The present overview of the 7th symposium on haplidentical transplantation that took place at the Weizmann Institute on February 2014, shows how these obstacles to successful transplantation can now be overcome. The review also discusses the advantages and drawbacks of current options for full haplotype-mismatched transplantation and highlights innovative approaches for rebuilding immunity, reducing leukemia relapse and improving survival after transplantation. In addition, new modalities for immune tolerance induction following nonmyeloablative conditioning are discussed, showing new options for treatment of elderly patients who cannot tolerate myeloablative conditioning protocols, as well as novel strategies for immune tolerance and chimerism induction as a platform for cell therapy and organ transplantation.