Marrow Transplants from Unrelated Donors as Treatment for Acute Leukemia

High-dose therapy followed by transplantation of allogeneic stem cells is a well established treatment for high-risk acute leukemias.1 This procedure combines the strong antineoplastic activity of the intensive regimen used for conditioning with the immune mediated effects of the graft against the leukemia. The success of allogeneic transplantation depends on the availability of a closely HLA-matched donor. Since only 30% of patients have such a donor in their family, one option for the remaining 70% is to identify an HLA-identical unrelated volunteer in the international registries.2 Despite the enormous polymorphism of HLA-genes, the probability of finding a suitable unrelated donor (URD) is increasing, since the registries contain more than 6 million I-ILA-typed volunteers worldwide. The probability of finding a donor matched at HLA-A, B and DR for a Caucasian patient is greater than 80%. The median time to identify a donor continues to decrease and is now 3.7 months in the U.S. This improvement is rel...