Objective: To improve the outcome of hematopoietic stem cell transplantation from unrelated donors.
Methods: Sixty-six patients with hematological diseases (40 cases of acute leukemia, 24 chronic myeloid leukemia, and one each severe aplastic anemia and beta-thalassemia) received bone marrow (BMT, n = 48) or peripheral blood stem cell transplantation (PBSCT, n = 18) from HLA-compatible unrelated donors after BUCY or TBI conditioning. Forty patients received longer and intensive GVHD prophylaxis (cyclosporin A from day -10 combined with mycophenolate mofetil).
Results: Sixty-four patients achieved sustained donor engraftment. The median time of leukocyte engraftment was 15 days, being significantly earlier in PBSCT group compared with BMT group (12 vs 16 days, P = 0.002). The cumulative incidence rates of grades I-II and III-IV acute GVHD at day 100 were 57.15% and 32.25%, respectively. Chronic GVHD was seen in 21 of the 36 evaluable cases and ten of them were extensive type. Six patients relapsed and 27 dead, the overall survival at 5 years was 52.91%. The COX method analysis showed that HLA-compatible level and source of graft affected the incidence of aGVHD. The patients transplanted from HLA-matched donor with high resolution and PBSCT had the less probability for aGVHD. Patients without GVHD or with longer and intensive GVHD prophylaxis had significantly improved OS.
Conclusion: The key to improvement the outcome of HCT from unrelated donor is to reduce the incidence and severity of aGVHD by selecting the HLA-matched donor, intensifying the immunosuppression at the early stage of transplantation.