• Engraftment, as defined by the persistent presence of donor-derived cells. [ Time Frame: 100 days to 5 year ] [ Designated as safety issue: Yes ]
  

• The mortality associated with transplant [ Time Frame: by day 100 ] [ Designated as safety issue: Yes ]
  
• Patient outcomes, based on differential imaging and biologic evaluations prior to transplantation and at designated points after transplantation [ Time Frame: day 100, 6 months, 1, 2 and 5 years ] [ Designated as safety issue: No ]
  

Procedure: Stem Cell Transplantation
The purpose of hematopoietic stem cell transplantation (HSCT) is to introduce blood producing cells from a normal donor, in this case, stem cells obtained from cord blood.
Drug: Campath, Busulfan, Clofarabine
• 12 Campath-1H 0.3 mg/kg intravenously over 2 hours
• 11 Campath-1H 0.3 mg/kg intravenously over 2 hours
• 10 Campath-1H 0.3 mg/kg intravenously over 2 hours
• 9 Busulfan <12 kg: 2.2 mg/kg/dose IV every 12 hours >12 kg: 1.6 mg/kg/dose IV every 12 hours
• 8 Busulfan <12 kg: 2.2 mg/kg/dose IV every 12 hours >12 kg: 1.6 mg/kg/dose IV every 12 hours
• 7 "Rest"
• 6 Clofarabine 40 mg/m2 intravenously over 2 hours
• 5 Clofarabine 40 mg/m2 intravenously over 2 hours
• 4 Clofarabine 40 mg/m2 intravenously over 2 hours
• 3 Clofarabine 40 mg/m2 intravenously over 2 hours
• 2 Clofarabine 40 mg/m2 intravenously over 2 hours
Procedure: Total Lymphoid Irradiation

Dose 500 cGy via AP and PA fields (250 cGy ANT and 250 cGy POST). Treated AP and PA with the patient on a specially designed couch on the floor. Doses rate 26 cGy/minute. Photon energy 6 MV used. Prescribed to the mid-thickness at the center of the field. Superior border is 2 cm below the mastoid tip. Inferior border is at the ischial tuberosity. Lateral border covers the axillary lymph nodes. Below the diaphragm the field is wide enough to encompass the liver and spleen and the mesenteric nodes.

Above the diaphragm the field encompasses cervical, infraclavicular, axillary, mediastinal, and hilar nodes.

Central block 2 cm in width partially shields the rectum, vagina, and bladder. Clam shell on the scrotum for all males if possible.

This transplant protocol will test the following: 1) the ability to achieve engraftment with the reduced intensity protocol, 2) the mortality associated with transplant by day 100, 3) patient outcomes, based on differential imaging and biologic evaluations prior to transplantation and at designated points after transplantation (day 100, 6 months, 1, 2 and 5 years). Additional biologic studies will include microarray analysis, Campath levels just prior to the administration of the graft, and establishment of mesenchymal stem cell lines. In older patients, studies to evaluation osteoclast differentiation and function will also be offered.