Allograft for Sickle Cell Disease and Thalassemia

The design of the study incorporates the following features: 1. This is a phase II study to determine the safety and therapeutic potential of a new transplant approach (disease-free survival, graft versus myeloma effect) and to evaluate its toxicity profile (immediate toxicity, graft-versus-host disease, graft rejection, mortality) in a patient population with severe congenital anemias. 2. The patient cohort to be studied: Those patients with severe sickle cell disease and thalassemia who have risk factors for high mortality and morbidity related to their disease 3. Transplant Conditioning Regimen - Immunosuppression without myeloablation: Patients will receive conditioning sufficient to allow donor lympho-hematopoietic engraftment without complete marrow ablation. If the graft is rejected, the patient will reconstitute autologous marrow function. We will use a combination of low dose irradiation, Alemtuzumab (Campath®), and sirolimus. 4. Peripheral blood hematopoietic progenitor cell (PBPC) transplant: An unmanipulated peripheral blood stem cell collection from a filgrastim (G-CSF) stimulated HLA-matched donor should improve the chance of engraftment because of the high stem cell dose (5 x 106/kg CD34+ cells) and the presence of donor lymphocytes. To reduce the risk of GVHD, patients will receive sirolimus before and after the transplant. The sirolimus will be tapered as necessary to minimize any graft versus host disease while still maintaining adequate chimerism.