Graft failure after allogeneic hematopoietic stem cell transplantation.

Graft failure is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) defined as either lack of initial engraftment of donor cells (primary graft failure) or loss of donor cells after initial engraftment (secondary graft failure). Successful transplantation depends on the formation of engrafment, in which donor cells are integrated into the recipient's cell population. In this paper, we distinguish two different entities, graft failure (GF) and poor graft function (PGF), and review the current comprehensions of the interactions between the immune and hematopoietic compartments in these conditions. Factors associated with graft failure include histocompatibility locus antigen (HLA)-mismatched grafts, underlying disease, type of conditioning regimen and stem cell source employed, low stem cell dose, ex vivo T-cell depletion, major ABO incompatibility, female donor grafts for male recipients, disease status at transplantation. Although several approaches have been developed which aimed to prevent graft rejection, establish successful engraftment and treat graft failure, GF remains a major obstacle to the success of allo-HSCT. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) still remains to be the curative treatment option for various non-malignant and malignant hematopoietic diseases. The outcome of allo-HSCT primarily depends on the engraftment of the graft. Graft failure (GF), is a life-threatening complication which needs the preferential therapeutic manipulation. In this paper, we focused on the definitions of graft failure / poor graft function and also we reviewed the current understanding of the pathophysiology, risk factors and treatment approaches for these entities.