Allogeneic hematopoietic cell transplantation (HCT) is the only known curative option for many hematologic disorders. After transplantation, many patients develop immune mediated disorders that may be life-threatening such as graft versus host disease (GVHD). The morbidity and mortality associated with HCT-associated immune mediated disorders are major barriers to successful use of transplantation to cure rare hematologic malignancies such as leukemia, lymphoma, multiple myeloma, myelodysplastic/myeloproliferative syndromes amongst other diseases.