Placental-derived and expanded mesenchymal stromal cells (PLX-I) to enhance the engraftment of hematopoietic stem cells derived from umbilical cord blood

For the past 40 years, bone marrow transplantation (BMT) has become standard therapy to re-establish marrow function in patients with damaged or defective bone marrow. A human leukocyte antigen-matched sibling is the donor of choice for patients needing transplantation of allogeneic hematopoietic stem cells (HSCs). As most patients do not have an acceptable matched, related donor, the National Marrow Donor Program has been established to match volunteer bone marrow donors with potential recipients who require BMT. Although transplantation of HSCs from an unrelated donor can be an effective therapy for a variety of malignant and non-malignant diseases, it remains complicated because of treatment-related morbidity and mortality, which has led to the investigation of alternative sources of HSCs such as umbilical cord blood (UCB). This review highlights the advantages and disadvantages of UCB and recent developments that address its disadvantages. This includes the use of a placenta-expanded mesenchymal stromal cell product (PLX-I) being developed by Pluristem Therapeutics, Inc. and our opinion about the potential of this product.