Graft Failure While complete and sustained engraftment is usually seen posttransplant, occasionally marrow function either does not return or, after a brief period of engraftment, is lost. Graft failure after autologous transplantation can be the result of inadequate numbers of stem cells being transplanted, damage during ex vivo treatment or storage, or exposure of the patient to myelotoxic agents posttransplant. Infections with cytomegalovirus (CMV) or human herpes virus type 6 have also been associated with loss of marrow function. Graft failure after allogeneic transplantation can also be due to immunologic rejection of the graft by immunocompetent host cells. Immunologically. | Chapter 108. Hematopoietic Cell Transplantation Part 6 Graft Failure While complete and sustained engraftment is usually seen posttransplant occasionally marrow function either does not return or after a brief period of engraftment is lost. Graft failure after autologous transplantation can be the result of inadequate numbers of stem cells being transplanted damage during ex vivo treatment or storage or exposure of the patient to myelotoxic agents posttransplant. Infections with cytomegalovirus CMV or human herpes virus type 6 have also been associated with loss of marrow function. Graft failure after allogeneic transplantation can also be due to immunologic rejection of the graft by immunocompetent host cells. Immunologically based graft rejection is more common following use of less-immunosuppressive preparative regimens in recipients of T cell-depleted stem cell products and in patients receiving grafts from HLA-mismatched donors. Treatment of graft failure usually involves removing all potentially myelotoxic agents from the patient s regimen and attempting a short trial of a myeloid growth factor. Persistence of lymphocytes of host origin in allogeneic transplant recipients with graft failure indicates immunologic rejection. Reinfusion of donor stem cells in such patients is usually unsuccessful unless preceded by a second immunosuppressive preparative regimen. Standard preparative regimens are generally tolerated poorly if administered within 100 days of a first transplant because of cumulative toxicities. However use of regimens combining for example anti-CD3 antibodies with high-dose glucocorticoids fludarabine plus low-dose total-body irradiation or cyclophosphamide plus antithymocyte globulin have been effective in some cases. Infection Posttransplant patients particularly recipients of allogeneic transplantation require unique approaches to the problem of infection. Early after transplantation patients are profoundly neutropenic and because the risk of .
