Abstract: TH-PO659
A 35-Year History of Lupus Nephritis Without Renal Fibrosis or Scarring: How Is This Possible? Exostosin 2
Session Information
- Glomerular Diseases: Epidemiology and Case Reports
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Trials
Authors
- Goggins, Eibhlin S., University of Virginia, Charlottesville, Rhode Island, United States
- Murphy, Joel D., Arkana Laboratories, Little Rock, Arkansas, United States
- Cavanaugh, Corey J., University of Virginia, Charlottesville, Rhode Island, United States
Introduction
Recently, Exostosin 1/Exostosin 2 (EXT1/2) was identified as a novel antigen in membranous nephropathy associated with autoimmune disease, particularly lupus nephritis (LN). These patients have distinct clinical features, notably favorable outcomes despite high proteinuria. Current guidelines provide treatment recommendations for patients with LN. However, whether these represent the best approach to the subgroup of patients with EXT1/2+ LN remains elusive.
Case Description
A 54-year-old female with a 35-year history of class IV & V LN presented with proteinuria/hematuria along with hair loss and rash. The patient was not on any immunosuppressive drugs and was taken off hydroxychloroquine 2 years prior for retinal toxicity. History was significant for HTN, osteoporosis hypovitaminosis D, AVN of hips and knees, nephrolithiasis, HLD, glaucoma, and hysterectomy for uterine fibroids. Serology showed negative ANA (previously positive), positive anti-dsDNA, low C3, and low C4. Kidney biopsy revealed membranous LN Class V with EXT2+, PLA2R-, THSD7A-, NELL1- staining. Notably, a near total lack of fibrosis or glomerulosclerosis was observed. Treatment was reinitiated with mycophenolate mofetil and tacrolimus for nephrotic syndrome, and losartan for HTN.
Discussion
Our patient has a long history of recurrent LN, with a notable lack of renal fibrosis or sclerosis. Further investigations revealed EXT2 positivity. Despite evidence demonstrating a favorable renal prognosis associated with EXT1/2+ LN, it is unclear whether these patients remain susceptible to other diseases, as persistent proteinuria can affect other clinical outcomes. Our patient had a recurrence of disease in the context of no immunosuppressive therapy. Without further evidence, we favor a standard approach to immunosuppressive therapy (as in EXT1/2 negative counterparts). We believe EXT1/2 immunohistochemical phenotyping of patients with LN should be performed to aid in our understanding of this subgroup. There are many outstanding questions regarding EXT1/2 and this case underscores the need for more research to help guide treatment practices.