Allogeneic hematopoetic stem cell transplantation (HCT) is used in the treatment of a variety of hematological, myeloproliferative and lymphoproliferative disorders, and malignancies involving solid tumors. Patients receiving HCT can develop a life threatening condition called graft versus host disease (GVHD). GVHD occurs when donor T cells from the donor bone marrow recognize host cells as "foreign" and initiate an inflammatory immunological response. The standard of care for treatment of acute GVHD consists of intravenous delivery of methylprednisolone starting on day 1 and continuation of either cyclosporine or tacrolimus. This regimen of steroids and immunosuppressive drugs may relieve symptoms of GVHD, but some patients are refractory to current standard of care treatment. For treatment-refractory patients with grades III-IV GVHD mortality is approximately 80%. A therapy that could effectively suppress the immunological response from GVHD and help repair the damaged tissue could significantly decrease the mortality rate from this disease.