Effect of Transfusion of the Third Party Umbilical Cord Blood on Haplo-Identical Hematopoietic Stem Cell Transplantation

Objective To retrospectively evaluate the effect of the third party umbilical cord blood on haplo-identical hematopoietic stem cell transplantation.

Methods   From June 2012 to May 2015, 125 leukemia patients were enrolled, including 41 cases of ALL, 62 cases of AML, 12 cases of MDS, 7 cases of CML-BP, 2 cases of acute mixed leukemia and 1 case of Mother cell dendritic cell tumor. Inclusion criteria: 1) AL patients; 2) halpo-identical HSCT; 3) 3/6 matched cord blood was available. Patients were divided into two groups, ie. groupA (HSCT, n=65) and groupB (HSCT plus umbilical cord blood transfusion group, n=60). Myeloablative conditioning regimens consisted of BuCy, TBI/FLAG, TBI/Cy, and FLAG that followed by reduced-intensified BUCY. The median dose of mononuclear cells in groupA and B were 8.58×10⁸/kg and 9.01×10⁸/kg, respectively. The median dose of CD34⁺ cells for transfusion in each group were 3.67×10⁶/kg and 2.94×10⁶/kg, respectively. The dose of grafted UCB MNCs and CD34⁺ cells for groupB were 3.5×10⁷/kg and 2×10⁵/kg, respectively. All patients received cyclosporineA, MMF and methotrexate for GVHD prophylaxis. The endpoints of this study were hematological engraftment, incidence of acute and chronic GVHD, incidence of relapse, transplant-related mortality(TRM), non-relapse mortality(NRM), Overall survival(OS) and Disease-free survival(DFS) in each group.

Results The median follow-up time was 17(3－29) months in groupA and 18(3－35) months in groupB. Patients in groupA reached a sustained ANC of more than 0.5*10⁹/L at a median of 11 days, whereas 14 days in groupB. Platelet more than 20*10⁹/L occurred at a median of 19 days in groupA, whereas 17 days in groupB (P= .4). The rate of aGVHD was not significantly different in the two groups, 56.9％ in groupA and 48.3% in groupB (P= .21). The accumulative incidence of II-IV grade aGVHD was 35.4％ in groupA and 30% in groupB (P= .42). The incidence of chronic GVHD was 79.2% in groupA and 71% in groupB (P= .47). The incidence of extensive type was lower in groupB, 69.2% Vs 35%，P=0.09. The incidence of CMV was lower in groupB, 80% Vs 60% (P= .01). The accumulative incidence of EBV was lower in groupB, 35.4% Vs 3.3% (P<0.01). At two years, the accumulative incidence of relapse was 24.4% in groupA and 17.2% in groupB, P=0.13. The two-year accumulative incidence of OS was 72.9% in groupA and 84.8％ in groupB，P=0.07. The one-year accumulative incidence of DFS in each group were 65.7％ and 79.4％，respectively，P=0.03. Conclusion  Our clinical results have shown that HSCT with transfusion of the third party umbilical cord blood is a promising modality for induction of immunity reconstitution. Better survival results may benefit from lower incidence of GVHD and virus infection.