Stem cell transplantation and gene therapy for hemoglobinopathies

The b-thalassemias and sickle cell disorders are the most common genetic diseases worldwide. Although improvements in conservative treatment have considerably improved the prognosis of hemoglobinopathies, stem cell transplantation remains the only cure for thalassemia and sickle cell disease. Results of transplants in these diseases have steadily improved over the last two decades due to improvements in preventive strategies, effective control of transplant-related complications and development of new preparative regimens. High-resolution human leukocyte antigen (HLA) typing has enabled physicians to perform transplant from unrelated volunteer donors for thalassemia with results comparable with those obtained employing an HLA-identical sibling. Current understandings of stable mixed chimerism (MC) in patients with hemoglobinopathies provide a rationale for the use of less intensive conditioning regimens and future gene therapy. Despite recent advances in animal models, the clinical application of gene therapy for hemoglobinopathies is unlikely to be a reality for at least near future. With the advances in transplantation for thalassemia, all sickle cell disease patients should be offered stem cell transplantation with an human leukocyte antigen (HLA)-identical donor. This review focuses on the current status of stem cell transplantation for hemoglobinopathies.