Post-transplant cyclophosphamide (PTCy) is a graft-versus-host disease (GVHD) prophylaxis strategy used in allogeneic hematopoietic stem cell transplantation, in which high-dose cyclophosphamide is administered on specific early post-transplant days to selectively deplete alloreactive donor and host T cells while sparing regulatory and hematopoietic stem cell populations, thereby permitting engraftment across greater donor-recipient HLA mismatch (including haploidentical donors) without a proportional increase in GVHD risk. The underlying principle — that timed post-transplant cytotoxic conditioning of the alloreactive T-cell compartment can substitute for or improve upon conventional calcineurin-inhibitor-based GVHD prophylaxis — extends from its original haploidentical-transplant context to matched-donor transplant settings, situating this within transplant immunology and hematologic oncology, specifically the study of donor-recipient immune tolerance and alloreactivity control.
Post-transplant cyclophosphamide (PTCy) is a graft-versus-host disease (GVHD) prophylaxis strategy used in allogeneic hematopoietic stem cell transplantation, in which high-dose cyclophosphamide is a…