OBJECTIVETo evaluate the clinical effect of umbilical cord blood transplantation (UCBT) in children with hematologic malignancies.

METHODSA retrospective analysis was performed on the clinical data of 37 pediatric patients with hematologic malignancies that consisted of 14 cases of acute lymphocyte leukemia, 9 cases of acute myeloid leukemia, 5 cases of juvenile myelomonocytic leukemia, 3 cases of chronic myeloid leukemia, 2 cases of acute mixed leukemia, 3 cases of myelodysplastic syndrome, and 1 case of lymphosarcomatous leukemia. Thirty-seven children with hematologic malignancies received UCBT from unrelated donors (34 cases) and related donors (3 cases). Grafts were 6/6 HLA-matched in 5 cases, 5/6 HLA-matched in 12 cases, 4/6 HLA-matched in 11 cases, and 3/6 HLA-matched in 9 cases. Before transplantation, these patients received rabbit antithymocyte globulin-containing conditioning regimen. The myeloablative conditioning regimen was given in 36 cases and the reduced-intensity conditioning regimen in one case. The median age of transplantation was 5.7 years, and the median weight was 20 kg. The grafts that contained a median of 6.2×10(7) total nucleated cells (TNC)/kg and 2.7×10(5) CD34(+) cells/kg were infused.

RESULTSThe median times to neutrophil engraftment and platelet engraftment were 12 days and 25 days, respectively, and the rates of neutrophil engraftment and platelet engraftment were 95% and 78%, respectively. The rate of neutrophil engraftment was positively correlated with the number of CD34(+) cells (P=0.011), while the rate of platelet engraftment was correlated with the numbers of CD34(+) cells and TNC (P=0.001; P=0.014). The incidence rates of acute and chronic graft-versus-host disease were 49% and 11%, respectively. The median follow-up was 54 months. The 5-year transplant-related mortality, overall survival, and disease-free survival were 27%, 57.4% and 41%, respectively.

CONCLUSIONSUCBT is an alternative source of hematopoietic stem cells for patients with hematologic malignancies.