Abstract: FR-PO0899
Fibrillary Glomerulonephritis in Systemic Lupus Erythematosus: Case Series Highlighting Sustained Remission with Rituximab
Session Information
- Glomerular Case Reports: Lupus, FSGS, Complement, and More
November 07, 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
- Ayehu, Gashu H., Northwell Health, New Hyde Park, New York, United States
- Aguirre, Michelle, Hospital Universitario Fundacion Alcorcon, Alcorcón, Community of Madrid, Spain
- Alexander, Renita, Northwell Health, New Hyde Park, New York, United States
- Jhaveri, Kenar D., Northwell Health, New Hyde Park, New York, United States
Introduction
Fibrillary glomerulonephritis (FGN) is a rare glomerular disease characterized by fibrillary deposits in the glomeruli. It is often idiopathic but can occur with systemic lupus erythematosus (SLE), although this is rare. Distinguishing FGN from lupus nephritis (LN) is critical due to differences in pathogenesis, management, and prognosis. We report two cases of FGN in long-standing SLE, highlighting diagnostic nuance and favorable response to rituximab.
Case Description
Case 1:
A 67-year-old woman with a 39-year history of SLE and prior class III lupus nephritis with rising serum creatinine (from 1.2 to 2.5 mg/dL) and new-onset proteinuria, urine protein-to-creatinine ratio (uPCR) ~0.7 g/g without lupus flare. Biopsy confirmed FGN with randomly arranged ~10 nm fibrils on electron microscopy, positive DNAJB9 staining, and no active LN. She received rituximab (1 g ×2 doses), reducing uPCR to 0.2–0.3 g/g and creatinine to 2.0 mg/dL. Two additional rituximab infusions over the next two years maintained remission.
Case 2:
A 55-year-old woman with a 22-year history of SLE and prior class V LN developed proteinuria (uPCR 2.5 g/g) with stable kidney function (creatinine 0.47 mg/dL) and no active lupus serologies. Biopsy showed early FGN with 12–15 nm fibrils and positive DNAJB9 staining, alongside quiescent class V LN. She was treated with rituximab (1 g ×2 doses) while on mycophenolate and hydroxychloroquine. uPCR improved to 0.2 g/g and creatinine remained stable (~0.5 mg/dL) without further rituximab.
Discussion
SLE-associated FGN is exceedingly rare and requires electron microscopy and, when available, DNAJB9 staining to differentiate it from LN. There is no established treatment for FGN, but both patients achieved proteinuria remission and renal preservation with rituximab. These cases highlight the need to recognize FGN in SLE patients with proteinuria and inactive lupus, as accurate diagnosis enabled steroid-sparing, targeted therapy. Given the rarity of SLE-associated FGN, this series offers actionable insight into the management of a poorly understood glomerular disease.