Kidney Week

Abstract: SA-PO771

Evolving ANCA Serotype in a Patient with Dialysis-Dependent ESKD

Session Information

• ANCA-Associated Vasculitis, Anti-GBM Disease, and Other RPGN
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Dock, Peter, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States

Peter Dock, DO

• Dylewski, James F., Denver Health Main Campus, Denver, Colorado, United States

James F. Dylewski, DO, FASN

Introduction

ANCA antibody serotype PR3 and MPO has become an increasing focus of care in patients with ANCA associate vasculitis (AAV) since antibody serotype seems to be a more reliable marker for prognosis, response rate, relapse risk, and outcome compared to a clinical diagnosis of GPA or MPA. Furthermore, these serotypes have been reported to have different geographic and genetic factors. Below is a case of a patient who switched serotypes which, to our knowledge, has not been previously described.

Case Description

Ms G is a 49 yo Latina female who initially presented in 2018 with diffuse alveolar hemorrhage and AKI. ANCA testing showed +MPO/+p-ANCA-AAV consistent with a clinical diagnosis of microscopic polyangiitis (MPA). Kidney biopsy was also consistent with ANCA associated pauci-immune GN. Unfortunately, Ms G’s disease was difficult to control, and she suffered from multiple disease relapses despite maintenance therapies. While she would clinically improve with re-induction therapies, she remained serologically positive. In December 2019, after multiple disease flares, she became dialysis dependent. After approximately 1 year on dialysis, ANCA and MPO antibodies became negative, and she no longer had features of active AAV. (Table 1)
In 2021, 2 years after becoming dialysis dependent, Ms G presented with increasing dyspnea. ANCA serologies were checked and yielded a new positive PR3 antibody (Table 1). Ultimately, her symptoms were attributed to non-ANCA related disease. However, she continued to have a PR3 antibody. In 2024, Ms G presented with upper respiratory symptoms and rash. Biopsy of the rash demonstrated a small vessel vasculitis consistent with AAV. though repeat ANCA testing was negative at that time.

Discussion

To our knowledge, Ms G is the first reported patient to have an evolution in her ANCA vasculitis from an MPO to a PR3 serotype. Additionally, this evolution occurred after the patient had been dialysis dependent for several years, a time when most AAV disease typically becomes inactive. This would suggest the AAV serotype in this patient represents a spectrum of disease rather than a distinct phenotype.

Table 1