Abstract
Allogeneic stem cell transplantation (allo-SCT) is now frequently performed for the treatment of hematological malignancies and aplastic anemia. However, graft-versus-host disease (GVHD) is still the major complication after allo-SCT producing immune deficiency, infection, organ damage, and occasionally a patient's death. The antigen-specific signal mediated by the T cell receptor (TCR) is essential for the activation of T cells; however, additional costimulatory signals are required for complete T cell activation. Therefore blocking strategies of costimulatory signals, CD28/B7, CD40/CD40L, et al., have been evaluated as targets of therapeutic intervention for GVHD after allo-SCT. It is very important to consider the way to induce a graft-versus-leukemia (tumor) effect without GVHD for successful clinical allo-SCT.
