Scotti Gerber, Jennifer De Marchi, Sara Gaspert, Ariana Fehr, Thomas Cippà, Pietro E. 2024 Introduction: JC-polyomavirus-associated nephropathy (JC-PVAN) is a rare cause of allograft dysfunction with only a few cases described in the literature. Case Presentation: we present 2 cases of JC-PVAN, both of which occurred >5 years after kidney transplantation. In both cases, transplant biopsies were performed because of worsening of kidney function. We found tubulitis and interstitial inflammation; immunohistochemistry was positive for SV40, but BK virus was not detected. The presence of JC virus confirmed the diagnosis of JC-PVAN. Immunosuppressive therapy was adopted, but in both cases graft function progressively deteriorated. Conclusions: our cases show that JC-PVAN, although much rarer than BK-PVAN, should be considered a possible cause of graft dysfunction even years after transplantation. Complete diagnostic workup, including kidney biopsy, is crucial for correct diagnosis and treatment. application/pdf https://localhost:5000/ark:/12658/srd1330483 https://susi.usi.ch/global/documents/330483 https://susi.usi.ch/documents/330483/files/Scotti Gerber_2024_Karger_CaseRepNephrolDial_JC Polyomavirus.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1159/000540294 info:eu-repo/semantics/altIdentifier/ark/12658/srd1330483 info:eu-repo/semantics/openAccess CC BY-NC Case reports in nephrology and dialysis. - 2024, vol. 14, no. 1, p. 148-157 Kidney transplantation Infection JC virus Polyoma nephropathy BK virus info:eu-repo/classification/udc/61 JC polyomavirus nephropathy : a rare complication late after kidney transplantation http://purl.org/coar/resource_type/c_6501