Bone marrow transplantation, also known as hematopoietic stem cell transplantation (HSCT) is the only curative treatment for many malignant disorders, such as aggressive types of leukemia and lymphoma. It is also increasingly used to treat disorders other than cancer. Unfortunately, successful outcomes following HSCT can be limited by either cancer relapse, or graft-versus-host disease (GVHD), a complication wherein the new, donor, immune system attacks the patient causing significant multi-organ injury and dysfunction, which can be fatal.