Polyomavirus nephropathy (PVN) is an emerging cause of renal transplant loss. Until now the risk factors of PVN are poorly understood. Tacrolimus (Tacr) and mycophenolate mofetil (MMF) are thought to be associated with a higher risk of developing PVN. However, the way in which Tacr or MMF might enhance the susceptibility for PVN remains largely unknown. In this prospective study we will analyze whether differences in immune-reactivity patterns (Th1, Th2, B cell and monocyte responses, sCD30, immunoregulatory antibodies) of renal transplant patients induced by different immunosuppressive regimens (cyclosporine A [CsA]/MMF, Tacr/MMF, Tacr/MMF with conversion to Tacr/Everolimus [ERL]) or by cytokine promoter gene polymorphisms may account for the different risks of developing PVN.~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).
The aim of this study is to characterize and evaluate risk factors of polyomavirus nephropathy (PVN) including the impact of three immunosuppressive regimens.