In recent years it has become evident that bone marrow (BM) derived mesenchymal stem cells have potent immunomodulatory effects. MSCs are pluripotent cells that can differentiate into several mesenchymal tissues, including fibroblasts, osteoblasts, adipocytes and chondrocyte progenitors. MSCs have potent immunosuppressive effects on T and B cells in vitro and in animal models of chronic inflammation. Encouraging results have been obtained in patients with steroid resistant acute and severe Graft versus Host Disease (GvHD). The investigators hypothesize that infusion of MSCs may similarly provide a novel treatment option in the treatment of patients with allograft rejection with less side effects than existing immunosuppressive therapies.This study will evaluate the safety and feasibility of MSC therapy in renal recipients.