This trial aims to determine the benefit of using mesenchymal stem cells obtained from donated umbilical cord blood as an immunosuppressive agent in liver transplant patients. The trial is being conducted at the Beijing 302 PLA Hospital and expects to recruit 50 subjects by February 2015. Participants in the trial will receive either standard immunosuppression treatment following their liver transplant (control group); or they will weekly injections of mesenchymal stem cells for 12 weeks, in addition to the standard immunosuppression treatment (experimental group). Participants will be monitored for complications and for changes in liver function tests.