Polyomavirus-associated Nephropathy after Renal Transplantation

Park, Sung Bae; Ahn, Hyung Joon; Kim, Yu Seun; Cho, Won Hyun; Kim, Hyun Chul

Abstract

The first clinical infections with polyomavirus (PV) were demonstrated in 1971, when BK virus was isolated from the urine after a kidney transplant recipient and JC virus from the brain of a patient who died of progressive multifocal leukoencephalopathy. Polyomavirus-associated nephropathy (PVAN) has become an important cause of allograft dysfunction and loss in kidney transplantation since first recognized in kidney transplant recipient with PVAN in 1995. Most cases of PVAN are caused by polyomavirus hominis type 1, known as BK virus and arise while the patient in on triple immunosuppressive combinations, often comprising tacrolimus and/or mycophenolate mofetil plus corticosteroids. Significant progress has been made, particularly in the area of diagnostic methods for PV, facilitating diagnosis, screening and monitoring of PV infection. Definitive diagnosis of PVAN requires allograft kidney biopsy. Immunologic control of PV replication can be achieved by reducing, switching, and discontinuing of the immunusuppressive agents. Cidofovir and leflunomide are used empirically in the treatment of PVAN. However, these antiviral agents are not approved for PVAN. Recently, investigational use at low-dose cidofovir (0.25~0.33 mg/kg intravenously biweekly) without probenecid should be considered for the treatment of cases refractory to decreasedmaintenance immunosuppression. PVAN had a serious consequence of kidney transplantation that increasingly cause for chronic allograft kidney loss. Despite reduction in immuo-suppression, allograft kidney loss occurred in 46% of transplant recipients with PVAN. PVAN recurred in 15% of retransplantations compared with 5% of primary kidney transplantations. However, retransplantation is not contraindicated for transplant recipient in whom a first allograft kidney lost due to PVAN. Recently, preemptive retransplantation can be considered in patients with allograft loss due to PVAN.