Non-myeloablative Allogeneic Hematopoietic Stem Cell Transplantation (NST) for Patients With Refractory Crohn's Disease

Patient eligibility Inclusion Criteria: 1. Age \>18 years and less than age 45 years at time of pretransplant evaluation and, 2. Ability to give informed consent. And either A or B A)An established clinical diagnosis of severe CD with disease onset before 16 years old (at least 71 genetic loci predispose to pediatric CD, Limbergen, JV. Annu. Rev. Genom. Human Genet. 2009; 10:89-116) that has failed therapy with prednisone, 5 ASA products and has failed an anti-TNF therapy. Failure is defined as a CDAI (appendix A) 250-400 or a Craig Severity Score that is \> 17 (appendix C). B)Relapse after an autologous HSCT with a CDAI (appendix A) 250-400 or a Craig Severity Score that is \> 17 (appendix C). Exclusion Criteria: 1. HIV positive. 2. History of coronary artery disease, or congestive heart failure. 3. Uncontrolled diabetes mellitus or any other illness that in the opinion of the investigators would jeopardize the ability of the patient to tolerate aggressive chemotherapy. 4. Prior history of malignancy except localized basal cell or squamous skin cancer. Other malignancies for which the patient is judged to be cured by local surgical therapy, such as head and neck cancer, or stage I breast cancer will be considered on an individual basis 5. Positive pregnancy test, lactation, inability or unwillingness to pursue effective means of birth control, failure to accept or comprehend irreversible sterility as a side effect of therapy. 6. Psychiatric illness or mental deficiency making compliance with treatment or informed consent impossible. 7. FEV 1/FVC \< 50% of predicted, DLCO \< 50% of predicted. 8. Resting LVEF \< 50%. 9. Bilirubin \> 2.0 mg/dl, transferase (AST) \> 2x upper limit of normal, unless the abnormalities are secondary to Crohn's disease. 10. Serum creatinine \> 2.0 mg/dl. 11. Platelet count less than 100,000/ul, ANC less than 1500/ul. 12. Patients presenting with intestinal perforation or toxic megacolon, or a suppurative problem that will require urgent surgery. In addition, the patient may not have any active infection. The presence of intestinal stomas does not exclude the patient from study. 13. Pre-study peripheral blood counts must include a platelet count greater than 100,000/ul and an absolute neutrophil count greater than 1500/ul. 14. Creatinine clearance more than 20% below lower limit of normal for age and sex. 15. Short gut syndrome. Donor eligibility Inclusion criteria 1\. Donor must be an HLA 6 out of 6 matched sibling Exclusion criteria of HLA matched sibling donor 1. Physiologic age \> 50 years old or \<18 years old 2. HIV positive 3. Active ischemic heart disease or heart failure 4. Acute or chronic active hepatitis 5. Uncontrolled diabetes mellitus or any other illness that in the opinion of the investigators would jeopardize the ability of the donor to tolerate stem cell collection 6. Prior history of malignancy except localized basal cell or squamous skin cancer. Other malignancies for which the patient is judged to be cured by local surgical therapy, such as (but not limited to) head and neck cancer, or stage I or II breast cancer will be considered on an individual basis. 7. Positive pregnancy test 8. Psychiatric illness or mental deficiency making compliance with treatment or informed consent impossible 9. Major hematological abnormalities such as platelet count less than 100,000/ul, ANC less than 1000/ul 10. Donor has history of Crohn's or ulcerative colitis