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.