[A comparative study of peripheral blood stem cell vs bone marrow transplantation from unrelated donors].

OBJECTIVE: To compare the outcomes in hematological patients receiving unrelated peripheral blood stem cell transplants (UPBSCT) with those receiving unrelated bone marrow transplants (UBMT) in a retrospective analysis. METHODS: Sixty-three patients with hematological diseases with HLA-matched (65%) or mismatched (35%) unrelated donors were receiving UPBSCT (n = 33) or UBMT (n = 30) between May 2001 and June 2005 in our institute. They all received standard conditioning regimens with Bu/Cy (n = 53) or TBI/Cy (n = 10) with the addition of ATG for 3 - 4 days (n = 58) or CD3 antibody (n = 5). There were more patients receiving rabbit ATG in the UPBSCT group than UBMT (21/33 vs 8/25, P = 0.02) and the remaining patients received pig ATG. Graft versus host disease (GVHD) prophylaxis consisting of cyclosporine, methotrexate and mycophenolate mofetil were the same. RESULTS: The two groups were matched for the following factors: gender, diagnosis, HLA-compatibility and conditioning regimens. The median age in the UPBSCT group was 29.5 (10 - 47) years and in the UBMT 21.5 (7 - 42) years (P < 0.05). The UPBSCT group consisted of 10 females and 23 males and the UBMT group 7 females and 23 males. Eleven patients in the UPBSCT and 8 patients in the UBMT group were diagnosed with as chronic myeloid leukemia (CML); 9 and 12 as acute myelocytic leukemia (AML); 11 and 10 as acute lymphatic leukemia (ALL); 2 and 0 as severe aplastic anemia (SAA). There were more patients in aggressive stage (>CR1) in the UBMT group than in the UPBSCT group (9/30 vs 3/33, P = 0.06). Median follow-up was 12 months after UPBSCT and 20 months after UBMT (P < 0.05). UPBSCT group had a higher number of infused MNC as comparison with UBMT group (6.16 x 10(8)/kg vs 2.80 x 10(8)/kg, P < 0.05). Both neutrophil and platelet recovery were faster after UPBSCT (11 days vs 17 days, 14 days vs 27.5 days, P < 0.01). Although the cumulative incidence of grades II - IV acute GVHD and severe aGVHD in the UPBSCT group were less than in the UBMT group (33.04% vs 66.69%, 7.26% vs 34.52%, P < 0.05), there was no difference after the source of ATG was counted. The incidence of chronic GVHD did not differ between the two groups (18/25 vs 14/22). Relapse including molecular relapse occurred in 6 of the 31 patients after UPBSCT and in 4 of the 30 patients after UBMT (P > 0.05). Finally, fifteen of the 30 patients died after UBMT, as compared with 8 of the 33 patients after UPBSCT. The cumulative overall survival was 62.45% after UPBSCT and 47.22% after UBMT (P = 0.114). CONCLUSION: Our results indicate that UPBSCT led to significantly faster leukocyte and platelet engraftment without increasing the incidence of aGVHD and the overall survival was comparable between the two methods of therapy.