Unrelated transplants can be considered as secondary therapy in children for whom a donor is located in HLA registries. As with marrow transplantation, results with immunosuppression have also improved over time. Similar excellent response rates have been obtained with an ATG plus cyclosporine regiment at the National Institutes of Health. All agreed that cyclosporine was an important addition to therapy. A potentially helpful role of growth factors was suggested by the routine use of G-CSF in the recent European study.
Immunosuppressive treatment has several major problems.
Relapse occurs in about one-third of patients, although most respond to a second course of immunosuppression and some will not relapse again. A more serious problem is the evolution of clonal hematologic disease. However, a significant proportion of patients may develop myelodysplasia or acute leukemia even many years after recovery of blood counts. Both the European and American experience with hematopoietic growth factors was reviewed. These treatments are not recommended as first therapy for patients with aplastic anemia, and the now common practice of treating patients with colony stimulating factors or erythropoietin before referral for either transplantation or immunosuppression was deplored.