Abstract: SA-PO0868
ANCA-Associated Glomerulonephritis with Severe Interstitial Infiltration
Session Information
- Glomerular Case Reports: ANCA, IgA, IgG, and More
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Lumbrazo, Kenneth M., Westchester Medical Center Health Network, Valhalla, New York, United States
- Klein, Michael, Westchester Medical Center Health Network, Valhalla, New York, United States
- Pullman, James M., Montefiore Einstein Medical Center, New York, New York, United States
- Im, Jaehyuck, Westchester Medical Center Health Network, Valhalla, New York, United States
Introduction
Granulomatosis with Polyangiitis (GPA) is an ANCA-associated vasculitis (AAV) involving the upper and lower respiratory tracts and kidneys, leading to rapidly progressive glomerulonephritis. Typical biopsy findings are crescentic/necrotizing glomerular lesions with minimal immune staining.
We report a patient who exhibited the classical symptoms of GPA, with biopsy confirmation of the diagnosis. However, biopsy showed severe interstitial neutrophilic infiltration of unknown cause. A literature search revealed that several cases of acute interstitial nephritis (AIN) associated with AAV have been reported.
This case was notable for the intensity of the interstitial nephritis and the presence of glomerulonephritis caused by anti-PR3 ANCA.
Case Description
A 66-year-old male presented with hearing loss, dyspnea, cough, and sinus pain. Admitted with hypoxia, black sputum, and renal failure. CT chest showed irregular lung nodules. Bronchoscopy revealed diffuse blood clots and airway inflammation. Urinalysis showed significant leukocyturia, hematuria, and proteinuria, with a UPCR over 20 g/day, indicating severe renal involvement. AAV was suspected due to multisystem involvement. Serology showed ANCA 1:640 and PR3ab 180:16, with negative MPO ab. Kidney biopsy confirmed ANCA-associated glomerulonephritis with ruptured Bowman’s capsules and severe interstitial inflammation. The patient would be started on dialysis during admission. Treatment included methylprednisolone followed by prednisone, rituximab, and avacopan. Dialysis was withdrawn, but his kidney function did not fully return to baseline.
Discussion
AIN associated with AAV is rare, with a recent case series compiling only 24 such cases. Severe glomerular lesions were even less common, seen in just 16.7% of cases. Our patient showed both ruptured Bowman’s capsules, indicating severe disease and severe dense neutrophilic infiltration with rare eosinophils. While AIN in AAV is typically linked to MPO-positivity (21/24 cases), this case involved the rarer PR3-positivity. Our case highlights the potential for a distinctly less common form of AAV subtype, manifesting severe anti-PR3 AAV with severe neutrophilic infiltrate. This AAV subtype warrants further investigation, as it may offer insights into the pathophysiology, treatment response, therapeutic strategies, and prognosis of PR3-positive AAV associated with AIN.