The Safety and Efficacy of Umbilical Cord Blood Mononuclear Cells in Patients With Secondary Poor Graft Function After Hematopoietic Stem Cell Transplantation

"Three dose groups are preset. The doses are 2.0×10\^6/kg/time, 3.5×10\^6/kg/time and 5.0×10\^6/kg/ time respectively, in accordance with the 3+3 dose escalation principle, and proceed in turn.~Each subject receives conventional treatment plus umbilical cord blood mononuclear cells therapy, with 4 consecutive intravenous infusions of umbilical cord blood mononuclear cells at 1 week intervals."

"According to the safety data of dose escalation stage, one dose group is selected for extension.~Each subject receives conventional treatment plus umbilical cord blood mononuclear cells therapy, with 4 consecutive intravenous infusions of umbilical cord blood mononuclear cells at 1 week intervals."