To discuss the role of allogeneic transplantation for the treatment of severe aplastic anemia.
Published reports for treatment of severe aplastic anemia were searched with Medline. Search terms included severe aplastic anemia, HLA-matched sibling, unrelated donor, hematopoietic stem cell transplantation.
Survival after HLA-matched sibling donor transplantation is approximately 80% in patients aged less than 20 years. Survival rates are lower in older patients ranging from 50-70%. The risks of transplant-related morbidity and mortality increase with age and explain the observed lower survival rates in older patients. Unrelated donor transplantation is reserved for patients who lack a matched related donor and have failed at least one course of immunosuppressive therapy. Survival after unrelated donor transplantation has also improved in recent years and largely attributed to the selection of donors who are fully HLA-matched to the patient. The risks of transplant-related complications are higher than after HLA-matched sibling transplantation. Graft-versus-host disease (GVHD) is higher; GVHD can lead to significant morbidity and mortality. Other frequent complications include graft failure and pulmonary complications. The use of peripheral blood progenitor cells has also contributed to higher GVHD risks and consequently excess deaths.
The results of allogeneic transplantation, from related and unrelated donors have improved substantially in the last decade. Early referral for transplantation, selection of HLA-matched donors and improved supportive care has contributed to the success of this treatment. The choice of graft used for transplantation is important regardless of donor type; bone marrow is the preferred graft.