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

Allogeneic transplantation has been a high-risk procedure, although non-myeloablative conditioning regimens (mini-transplantation) minimizes regimen related toxicity. The investigators, therefore, propose a phase I study of matched sibling allogeneic hematopoietic stem cell transplantation with non-myeloablative conditioning. In addition, graft versus host disease (GVHD) will be virtually eliminated by CAMPATH that removes donor T cells from the graft. The goal is to assess the toxicity/efficacy (phase I) of allogeneic non-myeloablative hematopoietic stem cell transplantation for high-risk Crohn's disease. In simplistic terms, this protocol is designed to ablate an aberrant immune system and then, similar to the use of marrow transplants for immunodeficient patients, reconstitute a new immune system with lymphocyte depleted marrow.