Table 4.

Main factors for post-hematopoietic stem cell transplantation relapse

Factors	Brief description	Ref.
Disease type	The relapse rate is highest in ALL patients, followed by AML patients and CML patients	[161]
Pretransplant disease status	The risk of relapse is significantly higher in nonremission patients and patients with a high level of residual leukemia cells before transplantation	[151]
Risk stratification	The level of risk is positively correlated with the relapse rate and negatively correlated with the disease-free survival rate	[162]
Stem cell source	Peripheral blood stem cells contain more lymphocytes with a more potent GVL effect; as a result, the relapse rate of BMT is higher than that of PBSCT	[163,164]
Preconditioning	Myeloablative preconditioning is more effective in reducing post-transplant relapse than reduced intensity conditioning and nonmyeloablative preconditioning; T cell depletion is associated with increased relapse rates in CML and AML	[164,165]
GVHD	Post-transplant GVHD, especially cGVHD, is associated with a significantly lower relapse rate and a higher survival rate	[166,167]

ALL: Acute lymphoblastic leukemia; AML: Acute myeloid leukemia; BMT: Bone marrow transplantation; cGVHD: Chronic GVHD; CML: Chronic myeloid leukemia; GVHD: Graft versus host disease; GVL: Graft versus leukemia; PBSCT: Peripheral blood stem cell transplantation; Ref.: Reference.