Clinical and pathological features of kidney transplant patients with concurrent polyomavirus nephropathy and rejection-associated endarteritis

Abstract

AIM: To describe the clinicopathologic features of concurrent polyomavirus nephropathy (PVN) andendarteritis due to rejection in renal allografts.METHODS: We searched our electronic records database for cases with transplant kidney biopsiesdemonstrating features of both PVN and acute rejection (AR). PVN was defined by the presenceof typical viral cytopathic effect on routine sections and positive polyomavirus SV40 large-T antigenimmunohistochemistry. AR was identified by endarteritis (v1 by Banff criteria). All cases were subjected to chart review in order to determine clinical presentation, treatment course and outcomes. Outcomes wererecorded with a length of follow-up of at least one year or time to nephrectomy.RESULTS: Of 94 renal allograft recipients who developed PVN over an 11-year period at our institution,we identified 7 (7.4%) with viral cytopathic changes, SV40 large T antigen staining, and endarteritis in thesame biopsy specimen, indicative of concurrent PVN and AR. Four arose after reduction of immunosuppression (IS) (for treatment of PVN in 3 and tuberculosis in 1), and 3 patients had no decrease of IS before developing simultaneous concurrent disease. Treatment consistedof reduced oral IS and leflunomide for PVN, and antirejection therapy. Three of 4 patients who developedendarteritis in the setting of reduced IS lost their grafts to rejection. All 3 patients with simultaneous PVN andendarteritis cleared viremia and were stable at 1 year of follow up. Patients with endarteritis and PVN arising in a background of reduced IS had more severe rejection and poorer outcome.CONCLUSION: Concurrent PVN and endarteritis may be more frequent than is currently appreciated and may occur with or without prior reduction of IS.