Kidney Week

Abstract: TH-PO0544

Concomitant Biopsy-Proven ANCA-Associated Vasculitis (AAV) and Skin IgA Vasculitis

Session Information

• Glomerular Diseases: IgAN, IgA Vasculitis, and More
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Nikfar, Shaya, University of California Los Angeles, Los Angeles, California, United States

Shaya Nikfar, MD

• Arman, Farid, University of California Los Angeles, Los Angeles, California, United States

Farid Arman, MD, FASN

• Sisk, Anthony, University of California Los Angeles, Los Angeles, California, United States

Anthony Sisk, DO

• Kamgar, Mohammad, University of California Los Angeles, Los Angeles, California, United States

Mohammad Kamgar, MD, FASN

• Nobakht, Niloofar, University of California Los Angeles, Los Angeles, California, United States

Niloofar Nobakht, MD, FASN

Introduction

AAV is a systemic autoimmune disease characterized by necrotizing small-vessel inflammation. Standard diagnosis relies on clinical presentation and serologic testing, where p-ANCA correlates with MPO antibodies and c-ANCA with PR3 antibodies. We present a case of biopsy-proven AAV with a positive p-ANCA but negative MPO and PR3 antibodies with concomitant IgAV.

Case Description

An 81-year-old woman with type 2 diabetes presented with multiorgan symptom involvement, including petechial rashes, oral ulcers, cough, dyspnea, bilateral pleural effusions, pericardial effusion, and slowly declining kidney function. Skin biopsy demonstrated leukocytoclastic vasculitis consistent with IgAV. Despite oral steroids, symptoms progressed with worsening rash and decreased urine output. Presentation labs are summarized in Table 1. Serologic testing showed positive p-ANCA, ANA, and anti dsDNA, but negative MPO and PR3 antibodies. Given the serologies, a renal biopsy revealed pauci-immune necrotizing crescents in two of 25 glomeruli, confirming AAV crescentic GN. Rituximab induction was initiated. Six months later, the patient had a creatinine of 1 with downtrending P-ANCA.

Discussion

This case highlights the discordance between the skin vasculitis and GN. While IgAV can present as IgAV nephropathy, in our patient, the findings from the skin and kidney biopsies were discordant, and the kidney biopsy dictated the management. The case highlights the importance of serological testing and kidney biopsy in confirming the underlying pathology in patients with IgAV.

Serologies at the time of the biopsy