<qa>  How many patients will be recruited?Methods: Forty patients will be recruited among our cohort of liver transplant recipients. The study will last 48 weeks. Inclusion criteria will be a liver transplantation more than 2 years ago, b stable graft function, b no history of autoimmune liver disease, c absence of rejection in the last 12 months, d Use of calcineurin inhibitors CNI as monotherapy, eabsence of rejection on baseline liver biopsy, d tacrolimus trough levels 3 ngml or cyclosporine C2 levels 30 ngml, e signature of the informed consent form. After screening procedure mycophenolate mofetil will be started week -4 at a dose of 500 mg twice a day for two weeks and then week -2 increased to 1000 mg twice a day and CNI will be reduced at the 50 of the initial dose. After two weeks week 0 CNI will be completely discontinuedcomplete IS conversion. The investigators will follow up patients every 4 weeks up to 48 weeks after the complete IS conversion. The complete study period will last 52 weeks. At baseline mRNA fron liver samples and peripheral blood mononuclear cells will be isolated. This mRNA will be used to evaluate whole genome expression using Affimetrix microarrays. Besides, T regulatory cells frequency will be measured using peripheral blood cell immunophenotyping at baseline and at the end of the follow up. Clinical variables will be evaluated to determined the evolution of renal function and other cardiovascular risk factors. 