ABSTRACT
Polyomavirus nephropathy (PVN) is primarily caused by a pro-ductive intra-renal BK virus infection. It is often an iatrogenic complication due to long term over immunosuppression and frequendy leads to chronic kidney dysfunction and failure. Post renal transplantation, PVN has emerged as a major problem affecting up to 10% of all kidney grafts, most commonly within the first 6-18 months post surgery. Recent advances in our understanding of the development and progression of PVN have resulted in the definition of clinically significant disease stages: A (early), B (florid) and C (sclerosing). This chapter provides a detailed description of polyomavirus induced acute and chronic renal injury. Morphologic changes are correlated with the clinical presentation and graft outcome. Key biologic aspects that are pertinent to patient management are highlighted. New morphology based’ strategies, i.e., urine electron microscopy and improved decoy cell analyses, to reliably diagnose PVN non-invasively are discussed and incorporated into an updated diagnostic algorithm for patient screening and monitoring.
