Objective: To establish rhesus haploidentical hematopoietic stem cell transplantation model by nonmyeloablative conditioning, and examine the effects of mesenchymal stem cells (MSC) in haploidentical transplantation.
Methods: The recipient haploidentical rhesus monkeys were conditioned with a nonmyeloablative regimen consisted of fludarabine, cyclophosphamide, 200 cGy total body irradiation, and rabbit anti-human thymocyte globulin. Cyclosporine A, mycophenolate mofetil and anti CD25 antibody were used for graft versus host disease (GVHD) prophylaxis. Rhesus monkeys in one group were given hematopoietic stem cell (HSC) only, while in the other group HSC combined with MSC. The differences in hematopoiesis recovery, chimerism level, and GVHD between the two groups were evaluated.
Results: Stable chimerism could be achieved in recipient monkeys. Hematopoiesis recovery was mainly related with chimerism level. MSC seemed capable of facilitating HSC engraftment, as there were more mixed chimerism and less GVHD occurrence in the HSC combined with MSC recipient group.
Conclusion: A rhesus haploidentical hematopoietic stem cell transplantation model is successfully established by nonmyeloablative conditioning. MSC was of great benefit to haploidentical transplantation.