Mesenchymal stromal cells in kidney transplantation.

Mesenchymal stromal cells (MSC) have emerged as one of the most promising candidates for immunomodulatory cell therapy in kidney transplantation. Here we describe novel insights into the MSC mechanism of action and provide an overview of initial safety and feasibility studies with MSC in kidney transplantation. Clinical studies of MSC-based cell therapy in kidney transplant recipients demonstrated the safety and feasibility of cell therapy and provide the first encouraging evidence of the efficacy of MSC in enabling the minimization of immunosuppressive drugs. In our initial experience with MSC-based therapy in kidney transplant recipients we carried out extensive clinical and immunological monitoring of MSC-treated patients and found possible biomarkers of MSC immunomodulation in some of them. Based on these biomarkers we identified a patient in whom complete discontinuation of immunosuppression has been achieved safely and successfully. Many issues should be addressed before MSC-based therapy becomes a standard treatment protocol for kidney transplantation. A better understanding of the MSC mechanism of action and the identification of biomarkers of response to therapy will inform the rational design of the most effective clinical protocol and the selection of patients amenable to safe immunosuppressive drug withdrawal.