Hematopoietic Stem Cell Transplantation (HSCT) Using CD34 Selected Mismatched Related Donor and One Umbilical Cord Unit

This method of stem cell transplantation is designed to overcome some of the limitations of other alternative donor transplant options. Use of unrelated umbilical cord unit (UCB) donors appears to allow a greater degree of HLA mismatch with acceptable rates of GVHD. However, when UCB transplant was studied in the adult population, investigators discovered several limitations. One major limitation with UCB was delayed engraftment, resulting in higher risk of infection in the early post transplant period. The limitations to cord blood transplant involve delayed engraftment resulting in early complications such as infections. The main limitation associated with haploidentical donors is the significant immunosuppression required to prevent/treat aGVHD. Use of this combined modality of transplantation appears to allow for rapid neutrophil engraftment from the haploidentical donor and coupled with long term hematopoiesis from the UCB donor, thus requiring less long term immunosuppression. This study tests a new method of bone marrow transplantation called combined haploidentical-cord blood transplantation. In this procedure, some of the blood forming cells (the stem cells) from a partially HLA matched (haploidentical) related donor are collected from the blood, as well as cells from an umbilical cord are transplanted into the patient (the recipient) after administration of a "conditioning regimen". A conditioning regimen consists of chemotherapy and sometimes radiation to the entire body (total body irradiation, or TBI), One of two 'conditioning regimens' which will be determined by the physician. 1. FLUDARABINE, MELPHALAN, ATG Fludarabine 30mg/m2(Days-7,-6,-5,-4,-3)-,Melphalan 70mg/m2(Day -3,-2), ATG 1.5mg/m2(Day-7,-5,-3,-1) 2. FLUDARABINE, BUSULFAN, 400 CGY TBI, ATG Fludarabine 50mg/m2(Day -6,-5,-4,-3,-2),Busulfan 3.2mg/kg(Day -5,-4,-3,-2) 400cGY Total Body Irradiation(TBI)Day-1,ATG 1.5mg/kg(Day-7,-5,-3,-1) Day 0 -Haploidentical donor and one umbilical cord blood unit infusion Filgrastim will be administered daily from day +1 until blood counts have completely recovered. Tacrolimus and another immunosuppressant, Cellcept, starting before transplant also to reduce the risks of graft versus host disease and to promote the growth of the graft. Tacrolimus will be given daily from two days before the transplant until at least three months after transplantation. Cellcept, will be tapered after the cells engraft.