Abstract: FR-PO0776
The Green Glow: A Rare Case of Atypical Anti-GBM Disease
Session Information
- Glomerular Diseases: ANCA Vasculitis, Anti-GBM Disease, and Crescentic GN
October 23, 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
- Ilagan, Justin, Mayo Clinic in Florida, Jacksonville, Florida, United States
- Ovincy, Cene, Mayo Clinic in Florida, Jacksonville, Florida, United States
- Schlesinger, Reid P., Mayo Clinic in Florida, Jacksonville, Florida, United States
- Manohar, Sandhya, Mayo Clinic in Florida, Jacksonville, Florida, United States
- Hickson, LaTonya J., Mayo Clinic in Florida, Jacksonville, Florida, United States
- Mao, Michael A., Mayo Clinic in Florida, Jacksonville, Florida, United States
Introduction
Atypical anti–glomerular basement membrane (anti-GBM) disease is an exceedingly rare variant of anti-GBM disease characterized by linear immunoglobulin glomerular basement membrane deposition without detectable anti-GBM antibodies. Unlike classic anti-GBM disease, estimated at approximately 0.04 cases per million people and fewer than 25 cases reported in the literature, atypical anti-GBM disease remains poorly characterized and diagnostically challenging. We present a case with gross hematuria and rapidly progressive acute kidney injury (AKI).
Case Description
A 57-year-old man with hypertension and chronic microscopic hematuria presented with Stage 3 AKI and gross hematuria. Urinalysis showed RBCs and nephrotic-range proteinuria (6,440 mg/24 hours). Serologic evaluation including anti-GBM antibodies, ANCA, complement levels, and monoclonal protein studies was unremarkable. Kidney biopsy revealed sclerosing crescentic glomerulopathy with focal global glomerulosclerosis, tubulointerstitial nephritis, and interstitial fibrosis/tubular atrophy. Immunofluorescence demonstrated diffuse linear IgG staining of glomerular capillary loops consistent with atypical anti-GBM disease. IgG subclass staining showed positivity for IgG1, IgG2, and IgG4. Anti-GBM seronegativity was confirmed across multiple assays. He had no pulmonary involvement. Treatment included plasma exchange, corticosteroids, prednisone taper, and oral cyclophosphamide. Despite initial improvement in CRP and urine output, kidney function progressively worsened requiring hemodialysis.
Discussion
This case highlights the diagnostic complexity of atypical anti-GBM disease. Kidney biopsy remains essential when hematuria, proteinuria, or kidney dysfunction persists despite negative serologies. In the absence of a measurable antibody titer, treatment endpoints for plasma exchange remain undefined. Surrogate markers including CRP and urine output provided limited and discordant guidance, underscoring the need for validated biomarkers to direct therapeutic decisions in this condition. Although often considered indolent, the course can be heterogeneous and in rare cases progress to kidney failure, as seen here. Optimal treatment strategies remain uncertain for this rare disease, though corticosteroids, cyclophosphamide, rituximab, and plasmapheresis have all been utilized. Increased recognition of atypical anti-GBM disease may improve earlier diagnosis and intervention .