JC Polyomavirus Nephropathy: A Rare Complication Late after Kidney Transplantation

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. (c) 2024 The Author(s). Published by S. Karger AG, Basel