Incompatibilities in ABO blood groups can result in a hemolytic anemia that may require transfusion or erythropoietin therapy. ABO incompatibilities reportedly have not caused GVHD or transplant rejection. If the patient has a high antibody titer they can receive a red cell-depleted transplant. Methotrexate is also used to prevent hemolysis. Incompatibilities caused by anti-patient antibodies in the donor can be reduced by plasmapheresis.