Six years' experience of tolerance induction in renal transplantation using stem cell therapy

Tolerance induction (TI) has been attempted with chimerism/clonal deletion. We report results of TI protocol (TIP) using stem cell therapy (SCT) included adipose derived mesenchymal stem cells (AD-MSC) and hematopoietic stem cells (HSC) in 10 living-donor related renal transplantation (LDRT) patients under non-myeloablative conditioning with Bortezomib, Methylprednisone, rabbit-anti-thymoglobulin and Rituximab, without using conventional immunosuppression. Transplantation was performed following acceptable lymphocyte cross-match, flow cross-match, single antigen assay and negative mixed lymphocyte reaction (MLR). Monitoring included serum creatinine (SCr), donor specific antibodies (DSA) and MLR. Protocol biopsies were planned after 100days and yearly in willing patients. Rescue immunosuppression was planned for rejection/DSA/positive MLR. Over mean 6±0.37year follow-up patient survival was 80% and death-censored graft survival was 90%. Mean SCr was 1.44±0.41mg/dL. This is the first clinical report of sustained TI in LDRT for 6years using SCT.