Fibrosis in Renal Allografts

Calcineurin inhibitors have significantly improved the one-year graft survival of renal allografts. However, chronic nephrotoxicity caused by calcineurin inhibitors contributes to the long-term decline in renal function in kidney transplant recipients. Approximately ninety percent of the protocol biopsies of renal allografts, performed at 18 months post transplantation, show histological lesions of chronic calcineurin nephrotoxicity . In recent years, two new non-nephrotoxic immunosuppressive drugs, i.e. mycophenolate mofetil and sirolimus, have become available for the prophylaxis of graft rejection in renal transplantation.

Three randomized clinical trials, comparing cyclosporine with sirolimus in combination with mycophenolate mofetil, reported a superior graft function at one year in sirolimus treated renal allograft recipients. However, data on long-term graft survival and histological lesions of protocol biopsies in sirolimus-treated renal transplant recipients, are currently lacking.

In analogy with previous observations in native kidney disease, Grimm et al. recently reported that interstitial fibrosis in protocol biopsies of renal allografts, at 6 months post transplantation, significantly inversely correlates with the subsequent graft survival One hundred recipients of a first renal allograft will be randomized to an immunosuppressive protocol based on cyclosporine (50 patients) or sirolimus (50 patients). Concommittant immunosuppression will be similar in both groups, and consists of Daclizumab as induction treatment (five iv gifts every two weeks), and mycophenolate mophetil and steroids as maintenance immunosuppression.

Randomization will be performed by centre to avoid centre-related bias. All patients will complete a follow-up of 12 months. Two core biopsies of the graft will be obtained in each recipient, at implantation and at 6 months. Serum creatinine and the estimated creatinine clearance (by the Nankivell and the Jellife method) will be monthly recorded.