To observe the effect of stem cell infusion on the development of acute graft- versus-host disease (aGVHD) in patients with malignant hematologic diseases after single-unit unrelated cord blood transplantation (sUCBT).
Definite diagnosis of malignant hematologic disease before transplantation, age, gender and race are not limited;
Participants were required to have achieved complete remission with negative minimal residual disease (MRD) prior to transplantation;
Participants who are proposed to receive sUCBT for the first time;
Eastern Cooperative Oncology Group (ECOG) score 0-2;
Those with severe organ dysfunction or disease, such as severe disease and dysfunction of the heart, liver, kidneys and pancreas;
Any life-threatening disease, physical condition, or organ system dysfunction that, in the opinion of the investigator, may compromise participant safety and put the results of the study at unnecessary risk; drug-dependent individuals; participants with uncontrolled psychiatric disorders; and individuals with cognitive dysfunction;
Participants in other clinical studies that may affect aGVHD within 3 months;
Those whom the investigator considers unsuitable for enrollment (e.g., those who anticipate that patients will not be able to adhere to the examination and treatment due to financial and other issues).