The rationale behind this study involves the need to better manage rejection in the intestinal allograft recipient. Although tacrolimus based immunosuppression has made intestinal transplantation feasible, the requisite need for chronic high dose immunosuppression in order to control rejection has inhibited the wide spread clinical use and practicality of intestinal/multivisceral transplantation. The measures needed to prevent graft loss have frequently resulted in lethal infections, the leading cause of death. This trial is significant for determining if this new strategy of allograft immune-modulation with low dose ex-vivo irradiation and simultaneous done bone marrow cell infusion will favorably affect short and long term outcomes by reducing the risk of allograft rejection.