Allogeneic bone marrow transplantation: acute and late complications.

Allogeneic bone marrow transplantation (BMT) following high-dose marrow-ablative chemoradiotherapy, has been established as the treatment of choice for various hematologic, neoplastic, and congenital disorders. This procedure is performed to restore lymphohematopoiesis in patients with bone marrow failure states, to replace a diseased marrow by a healthy donor marrow, and as "rescue" to reconstitute lymphohematopoiesis following marrow-ablative chemoradiotherapy to eradicate a malignancy. Only 30 percent of patients requiring marrow transplantation have an HLA-compatible sibling and very few patients have an identical twin donor (syngeneic graft). Over the past few years, marrows from unrelated HLA-compatible donors have been used with increasing frequency and promising outcome in certain hematologic malignancies. Infectious complications, graft-versus-host disease, veno-occlusive disease of the liver, leukemic relapse, and graft failure, remain major obstacles adversely affecting the outcome of patients undergoing allogeneic BMT. Despite these complications, allogeneic BMT remains a highly successful therapeutic procedure associated with a 20% to 90% long-term disease-free survival in a variety of patients.