OBJECTIVETo evaluate relevant prognostic factors of unrelated single unit umbilical cord blood hematopoietic stem cell transplantation (sUCBT), and to explore the correlation between cryopreservation time of cord blood and cell viability and outcome of sUCBT.

METHODSRetrospective analysis of 137 patients undergoing sUCBT with cord blood provided by Shanghai Cord Blood Bank from Mar. 15, 2007 to Dec. 26, 2013 were performed in this study. The mean cryopreservation time of 137 units cord blood was 698(96-1968) days, with mean cell viability of 87.4% after thawing.

RESULTSNo statistical difference on cell viability, hematopoietic reconstitution, graft failure, acute graft versus host disease (GVHD) and overall survival (OS) was found between patients transfused with cord blood preserved below and above 2 years. The 5-year OS of patients transfused with cord blood preserved below and above 2 years were 55.6% and 67.9%, respectively (P=0.124). OS of the UCBT at 2011 and before, and after 2011 was 48.7% and 79.6%, respectively (P=0.001). Age above 16-year-old (RR=2.830, P=0.027) and UCBT at 2011 and before (RR=0.203, P<0.001) were two risk factors of treatment related mortality.

CONCLUSIONOutcome of sUCBT in China had significant improvement in recent 2 years. Cryopreservation time of cord blood had no statistical correlation to cell viability after thawing and clinical outcome.