Immune Checkpoints and targeted agents in relapse and graft-versus-host disease after hematopoietic stem cell transplantation

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for malignant hematologic disorders. Novel anti-infection agents have successfully decreased the risk of fatal infections post-HSCT in recent years, but the relapse of primary disease and graft-versus-host disease (GVHD) remain the major causes of death for transplant recipients, and significantly deteriorate the quality of life. Thus, it is crucial to maintain the immune homeostasis in transplant recipients and balance the graft-versus-leukemia (GVL) effect and GVHD. Methods: We reviewed the recently published literatures on immune checkpoint (IC) and targeted agents in relapse and GVHD after allogeneic HSCT Results: Emerging data suggest that IC is an attractive target to modulate immune responses, and accumulating evidences of IC-targeted agents have been published for the treatment of malignancies and autoimmune disorders. The unique mechanism of IC-targeted agents, which affects the immune homeostasis of the transplant recipient by modulating alloreactivity, minimizes the risk of organ toxicity and immunosuppression associated with conventional therapy Conclusion: There is an increase in literature reporting the application of immune checkpoint-targeted agents in HSCT settings, and an overview will benefit further exploration in this field