Autologous Transplant Targeted Against Crohn's

The autologous hematopoietic stem cell transplantation (HSCT) in this study utilizes a new non-myeloablative conditioning regimen in patients with high-risk Crohn's disease (CD). The regimen includes two types of chemotherapy (cyclophosphamide and fludarabine) as well as alemtuzumab. The regimen will include low-dose immunosuppressive therapy with tacrolimus (Prograf) for one year post-HSCT in attempt to prevent relapse and improve long-term remission. Patients will also receive rifaximin (Xifaxan) for six months post-HSCT to target abnormal intestinal microbiota that may trigger intestinal inflammation. The ability of these experimental treatments to stop relapses and progression (worsening) of Crohn's disease will be assessed.