Expanding the Donor Pool for Hematopoietic Stem Cell Transplantation Using Partial Match Parity

Recent advancements in hematopoietic stem cell transplantation (HSCT) have opened new horizons for patients with blood cancers who previously struggled to find compatible donors. A groundbreaking study demonstrates that utilizing donors with partial HLA compatibility—achieved through the concept of partial match parity—can lead to successful outcomes comparable to those with fully matched donors. This approach involves selecting donors with a 6/8 or 7/8 HLA match from large public registries and administering post-transplant cyclophosphamide, an immune-suppressing drug, to mitigate graft-versus-host disease (GVHD). The study, led by Dr. Antonio Jimenez Jimenez at the University of Miami, included 145 adult patients who received peripheral blood stem cells prepared with either reduced-intensity, nonmyeloablative, or myeloablative conditioning. Results showed one-year survival rates of approximately 79% to 84%, with low incidences of severe chronic GVHD, even among patients with lower HLA matches. These promising findings suggest a paradigm shift in donor selection, making HSCT accessible to a broader patient population, especially those from underrepresented groups or lacking fully matched donors. The strategy leverages the immunosuppressive properties of cyclophosphamide to prevent adverse immune reactions, traditionally a major hurdle in partial match transplantations. This development is significant as it expands the donor pool without compromising safety or efficacy, offering hope for more inclusive and effective treatment options for blood cancer patients worldwide.