AIMS AND STUDY DESIGN This a pilot, explorative study to define the safety and biological/mechanistic effect of the systemic intravenous infusion of syngeneic ex-vivo expanded MSCs in living-related kidney transplant recipients (one or two HLA haplotype mismatches) under basiliximab/low-dose RATG induction therapy and maintenance immunosuppressive drugs with the ultimate objective to test the feasibility of safely achieving graft tolerance in a subsequent efficacy pilot study. Indeed, to complement the research with a clinical portion that document operational tolerance, a pilot efficacy study of safely achieving kidney graft tolerance after complete withdrawal of maintenance immunosuppressive therapy will follow pending on the fact that the results of biological/mechanistic tests will document that MSC infusion allows the development of an immune microenvironment permissive to graft tolerance.