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Abstract: SA-PO236

BK Virus Nephropathy (BKVN) in a Native Kidney of an Immunosuppressed Patient

Session Information

Category: Onconephrology

  • 1700 Onconephrology

Authors

  • Ayah, Omar A., The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
  • Dande, Gabriela, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
  • Nyabera, Akwe, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
  • Farkash, Evan A., University of Michigan Medical School, Ann Arbor, Michigan, United States
  • Nassar, Tareq Issa, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
Introduction

BK virus nephropathy (BKVN) is common in kidney allografts but in native kidneys, BK reactivation is typically transient. However, there are a growing number of reports of native kidney fulminant BKVN in immunocompromised patients. We present a case of a patient with native BKVN mimicking an ifosfamide-related karyomegalic-like nephritis.

Case Description

A 53-year-old male with a past medical history of marginal zone lymphoma with transformation to diffuse B-cell lymphoma presented with worsening serum creatinine. He was in remission after chemotherapy including R-CHOP (2018-2019), R-ICE (2019), CD 19 CAR-T cell therapy (2019 –2020), fludarabine and cyclophosphamide lymphodepletion, and Obinutzumab with Brentuxumab vedotin (2020- 03/2021). 1 year after his last treatment, serum creatinine rose from a baseline of 0.99mg/dL to 2.13mg/dL. Urine protein-creatinine ratio was 223mg/g. Kidney biopsy showed interstitial nephritis with marked epithelial atypia, initially diagnosed as karyomegalic-like interstitial nephritis, likely related to treatment with ifosfamide. High-dose steroids were initiated without further improvement. Serum creatinine and UPCR increased when steroids were tapered. Cellcept was added to his regimen, as reported in other case reports, but his kidney function further declined. Cellcept was discontinued due to gastrointestinal side effects. An external review of pathology slides was obtained, and immunohistochemistry for Large T Antigen showed diffuse positivity, diagnostic of BKVN. Despite immunosuppression cessation the patient progressed to home hemodialysis.

Discussion

Non-kidney solid organ transplantation (32%) and hematologic malignancy (15%) are the most common associations with native kidney BKVN, which frequently progresses to end stage kidney disease. Pathologic hallmarks of BKVN in allografts such as plasma cell-rich infiltrates and nuclear inclusions are often subtle or absent in native BKVN. Interestingly, most cases of native BKVN associated with hematologic malignancy occur in the setting of ongoing treatment or active neoplasia, while this patient presented in remission.
This case highlights the challenging nature of native BKVN diagnosis, and the importance of having a high index of suspicion for BKVN and other viral infections in patients with active or recent immunocompromise or immunosuppression.