Kidney Week

Abstract: FR-PO0463

Late-Onset Immune Checkpoint Inhibitor-Induced Acute Interstitial Nephritis

Session Information

• AKI: Case Reports - TMA, Vasculitis, Immune-Mediated Injury, and Systemic Disease
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Tahir, Maria, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Maria Tahir, MD

• Trivedi, Naman, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Naman Trivedi, MD, FASN

• Siddiqi, Mahwash, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Mahwash Siddiqi, MD

• Raza, Muhammad, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Muhammad Raza, MD

• Abendroth, Catherine, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Catherine Abendroth, MD

• Verma, Navin, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Navin Verma, MD

• Ghahramani, Nasrollah, Penn State Health Milton S Hershey Medical Center, Hershey, Pennsylvania, United States

Nasrollah Ghahramani, MD, FASN

Introduction

Immune checkpoint inhibitors(ICIs) have transformed treatment in renal cell carcinoma(RCC). Adjuvant pembrolizumab has shown improved disease-free and overall survival in high-risk RCC following nephrectomy and is FDA approved for this indication.However,increasing ICI use has led to rise in immune-related adverse events(IRAEs),including ICI-associated acute kidney injury(ICI-AKI). Renal toxicity may occur months after discontinuation of therapy,making diagnosis difficult. Proton pump inhibitors(PPIs),frequently prescribed in patients receiving immunotherapy,are independently associated with acute interstitial nephritis(AIN),chronic kidney disease(CKD) and increase the risk of ICI-AKI.

Case Description

63-year-old man with type 2 diabetes mellitus,hypertension,CKD stage3b(baseline creatinine 2 mg/dL),metastatic clear cell RCC status post right partial nephrectomy,and neuroendocrine tumor presented with acute kidney injury(creatinine 7.79mg/dL)two months after last pembrolizumab dose.He was taking omeprazole for several months for GERD and reactive gastritis.Initial differential diagnoses included pre-renal azotemia,contrast-induced nephropathy,and radioligand therapy-associated nephrotoxicity.Kidney function failed to improve with intravenous hydration.Urinalysis showed minimal proteinuria with preserved urine output.Renal biopsy demonstrated interstitial lymphocytic inflammation involving scarred and non-scarred parenchyma,focal acute tubulitis,scattered eosinophils,moderate interstitial fibrosis and tubular atrophy,consistent with acute interstitial nephritis.He was treated with oral prednisone 60mg daily followed by taper,resulting in significant improvement in kidney function.Omeprazole was discontinued and replaced with famotidine. At follow-up,creatinine improved to 2.42mg/dL.

Discussion

ICI-AKI occurs in 2–5% of patients receiving ICIs.Risk factors include older age,underlying CKD,other nephrotoxic medications,and prior extra-renal IRAEs. PPIs are an important contributor to kidney-related adverse events in patients receiving ICIs and potentiate immune-mediated renal injury.
This case highlights the importance of maintaining high index of suspicion for late-onset ICI-induced AIN,even months after discontinuation of immunotherapy.Careful review of concomitant medications,is essential.Early kidney biopsy remains critical for confirming diagnosis,excluding alternative etiologies, and guiding prompt treatment.