Feasibility and safety of peripheral blood stem cell transplantation from unrelated donors: results of a single-center study

We compared the outcomes in patients receiving unrelated peripheral blood stem cell transplants (PBSCT) with those receiving bone marrow transplants (BMT) in a matched pair analysis, Seventy-four patients with hematological malignancies with HLA-matched (77%) and mismatched (23%) donors were analyzed in this study. Thirty-four patients (45%) were considered as high risk patients. Sixty-eight patients received standard conditioning regimens with Bu/Cy or TBI/Cy, Six patients received an intensified conditioning regimen with the addition of etoposide, thiotepa or melphalan, GVHD prophylaxis consisted of prednisolone, cyclosporine and methotrexate, Groups were matched for patient, donor, transplant characteristics and HLA compatibility, Peripheral blood stem cell collection led to the collection of a higher number of CD34(+) and CD3(+) cells in comparison to bone marrow collection, Leukocyte engraftment in the PBSCT group occurred in 14 days (median; range 6-26 days) and in the BMT group in 19 days (range 9-29 days; P < 0,02), The time of platelet engraftment did not differ significantly. The incidence of grades II-IV acute GVHD in the group of HLA-identical patients was 35% in the PBSCT group and 25% in the BMT group (P < 0,33, log-rank). However, there was a significant difference (P < 0,05, log-rank) in incidence and time to onset of acute GVHD II-IV comparing all patients, including the 17 mismatched transplants. Disease-free survival was 51% (19 patients) with a median of 352 days and 59% (21 patients) with a median of 760 days for PBSC and BMT transplants, respectively. In conclusion, our results indicate that allogeneic PBSCT led to significantly faster leukocyte engraftment but is associated with a higher incidence and more rapid onset of severe acute GVHD comparing all patients, including the 17 mismatched transplants. However, the incidence of severe acute GVHD in HLA-identical patients was not different between the PBSCT and BMT groups.