Kidney Week

Abstract: SA-PO873

A Rare Case of Concurrent IgA Nephropathy and Anti-glomerular Basement Membrane (GBM) Disease

Session Information

• Glomerular Diseases: Case Reports - 2
  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

• Xu, Phoenix, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Phoenix Xu, MD

• Maheshwari, Rahul, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Rahul Maheshwari, MD

• Gandarillas Fraga, Sebastian, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Sebastian Gandarillas Fraga, MD

• Ward, Stephen C., Icahn School of Medicine at Mount Sinai, New York, New York, United States

Stephen C. Ward, MD, PhD

• Vassalotti, Joseph A., Icahn School of Medicine at Mount Sinai, New York, New York, United States

Joseph A. Vassalotti, MD, FASN

• Chung, Miriam, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Miriam Chung, MD

• Yu, Samuel Mon-Wei, Icahn School of Medicine at Mount Sinai, New York, New York, United States

Samuel Mon-Wei Yu, MD

Introduction

Anti-glomerular basement membrane (anti-GBM) disease is a rare disorder, characterized by rapidly progressive glomerulonephritis (RPGN) with or without pulmonary involvement. Here, we report a patient presenting with RPGN due to anti-GBM disease, who was found to have mesangial IgA staining on immunofluorescence (IF), suggesting concurrent IgA nephropathy (IgAN).

Case Description

A 38-year-old male with no known past medical history, presented with several days of abdominal pain, nausea, and vomiting. He was found to have acute kidney injury with initial serum creatinine of 7.9 mg/dL requiring hemodialysis. Initial workup included a urinalysis with +4 protein; innumerable RBCs and 5-10 WBCs per HPF; a urine protein-to-creatinine ratio of 3.10 g/g; and an unremarkable kidney ultrasound. Serologic workup was notable for an IgG anti-GBM titer of 2.5 units/mL (reference < 0.9), and anti-nuclear antibody (ANA) titer of 1:320. Other serological studies including MPO, PR3, C3, C4, hepatitis B and C, and PLA2R were normal or negative.
Kidney biopsy light microscopy showed 25 glomeruli (20 with cellular and/or fibrous crescents, and 1 with mesangial expansion and hypercellularity). There was moderate interstitial scarring. IF showed linear staining of glomerular basement membrane for IgG (1+) and lambda/kappa (2+) consistent with anti-GBM glomerulonephritis. Additionally, mesangial regions were positive for IgA (1-2+), IgM (1+) and C3 (1+), consistent with IgA nephropathy.
Patient received pulse dose glucocorticoids, oral and intravenous cyclophosphamide, and 10 sessions of plasmapheresis. He remained on kidney replacement therapy after induction treatment with an anti-GBM titer of 0.2 units/mL.

Discussion

Concurrent IgAN with anti-GBM disease has been described sporadically in the literature with heterogeneous findings. These findings include linear IgA staining of GBM, concurrent mesangial IgA and linear IgG staining, and linear IgG staining with circulating IgA anti-GBM antibodies. The moderate scarring, mesangial involvement, and variable stages of crescent formation suggest that our patient may have had ongoing undiagnosed IgAN that preceded development of anti-GBM disease. Unlike other similar reported cases, he unfortunately did not have kidney function recovery.