Comparison(s): renal transplant recipients stratified according to their relative immunological risk (group 1: low risk (primary recipients without pre-immunization [PRA < 5%]); group 2: moderate risk (group 2a: primary recipients with low pre-immunization [PRA 6-20%]; group 2b: re-transplanted patients); group 3: very high risk (re-transplanted patients with a history of vascular rejection or recipients of a first graft with high pre-immunization [PRA > 20%]) randomized to be treated with one of three immunosuppressive regimens (CsA/MMF, Tacr/MMF, Tacr/MMF with subsequent conversion to Tacr/ERL).