This trial aims to evaluate the use of umbilical cord stem cells in treating active, refractory Systemic Lupus Erythematosus. The trial is being conducted by the Affiliated Nanjing Drum Tower Hospital and Nanjing University Medical School and proposes to recruit 40 patients between January 2012 and December 2013. Participants will receive an infusion of mesenchymal stem cells obtained from donated umbilical cord blood. Participants will be monitored for complications following the injection and changes in clinical condition, including lupus serology and kidney function.