Immunoablative Mini Transplant (Hematopoietic Peripheral Blood Stem Cell Transplant [HPBSC])

The standard treatment in many disorders of the bone marrow is high dose chemotherapy and whole-body radiation treatment followed by the stem cell transplant. This type of transplant not only suppresses or kills off the immune system, but is very toxic to the bone marrow. This study uses a chemotherapy regimen that will suppress the patient's immune system; however, it is non-myeloablative (not toxic to the bone marrow). It does not use whole-body radiation treatment. This approach can minimize the short- and long-term effects of transplantation. Other studies have shown that using chemotherapy followed by bone marrow transplantation without whole-body radiation can produce similar results as treatment with whole-body radiation. Patients will be given chemotherapy with Fludarabine and Busulfan prior to the stem cell transplant. This treatment not only destroys diseased cells, but it also kills normal bone marrow cells. Following this experimental treatment, the patient will be given the stem cells through a central venous catheter (tube inserted in a vein). When the healthy stem cells are given to the patient, they will replace the destroyed bone marrow cells and produce new blood cells. The Allogeneic (not one's own) stem cells used in this experimental transplant will be obtained from a related matched donor or from an unrelated matched donor located through the National Marrow Donor Program.