Recently, the team led by Professor Junren Chen from the Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences, along with Professor Zimin Sun’s team from The First Affiliated Hospital of the University of Science and Technology of China, conducted a retrospective analysis of 620 unrelated cord blood transplant cases in Anhui. They discovered that the required dose of CD34+ cells could be significantly lower than the target dose currently recommended by clinical guidelines without negatively impacting bone marrow recovery. Through nonlinear analyses, the researchers confirmed that there is no definitive threshold dose of CD34+ cells necessary to ensure successful transplantation and avoid graft failure.In one remarkable case from the cohort, a patient received a CD34+ cell dose as low as 0.2×10⁵/kg (with a nucleated cell dose of 1.8×10⁶/kg), yet achieved granulocyte recovery 24 days post-transplant. This dose is an order of magnitude lower than the 0.2×10⁶/kg target recommended by the European Society for Blood and Marrow Transplantation (EBMT) Handbook. Based on data showing that approximately one out of every 9.3×10⁵ nucleated cells in human cord blood can successfully engraft in the bone marrow of SCID mice, the researchers estimated that this patient was infused with approximately 100 SCID-repopulating cells (SRC).The study also found that calculating the CD34+ cell dose per liter of recipient blood volume, rather than per kilogram of recipient body weight as recommended by current clinical guidelines, better predicts the time required for granulocyte recovery.
To explore whether their findings based on the cord blood cohort could be applied to non-cord blood transplants, the researchers analyzed 746 cases of mobilized blood transplantation from HLA-matched sibling donors in Tianjin and Anhui between 2013 and 2021.
On September 25, 2024, Professors Junren Chen, Erlie Jiang, and Zimin Sun published their findings in Leukemia under the title “New Criteria for Estimating Numbers of CD34-Positive Cells in a Graft Needed for Post-Transplant Bone Marrow Recovery.”
