Kidney Week

Abstract: FR-PO0712

Crescents and a "Full House" in Sjögren Syndrome: EXT1-Positive Secondary Membranous Nephropathy

Session Information

• Glomerular Diseases: Membranous Nephropathy, FSGS, and Podocytopathies
  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

• Nemalidinne, Krishna Vani, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States

Krishna Vani Nemalidinne, MD

• Vanteru, Abinay Siva kumar Reddy, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States

Abinay Siva kumar Reddy Vanteru, MD

• Mahmoud, Saad Abdulrahim Talal, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States

Saad Abdulrahim Talal Mahmoud, MBBS

• Alzghoul, Husam Mohammad, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States

Husam Mohammad Alzghoul, MD

• Ravula, Sreelakshmi, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States

Sreelakshmi Ravula, MD

Introduction

EXT1/EXT2-positive membranous nephropathy (MN) has emerged as a distinct autoimmune-associated subtype, often linked to lupus-like disease. Renal involvement in Sjögren syndrome (SS) more commonly presents as tubulointerstitial nephritis or membranoproliferative glomerulonephritis, while MN is uncommon. We describe an unusual case of EXT1-positive secondary MN associated with SS, presenting with crescents and a full-house immunofluorescence (IF) pattern

Case Description

A 68-year-old African American woman with SS, psoriatic arthritis on an IL-23 inhibitor, type 2 DM, hypertension, chronic kidney disease, and remote ductal carcinoma in situ status post bilateral mastectomy presented with anasarca and acute kidney injury. Baseline creatinine was 1.3 mg/dL, increasing to 5.0 mg/dL on admission. Laboratory evaluation demonstrated nephrotic syndrome with 24-hour urine protein of 14 g/day and serum albumin of 2.1 g/dL.
Serologic evaluation was unrevealing, including negative PLA2R antibody, ANA, ANCA, anti-GBM antibody, cryoglobulins, hepatitis panel, HIV, and syphilis testing, and normal Complement levels, negative SPEP/UPEP, with immunofixation. Kidney biopsy revealed MN with focal crescents, diffuse ATI, diabetic nephropathy, and moderate IFTA. IF demonstrated full-house staining. PLA2R, THSD7A, NELL1, and NCAM staining were negative, while EXT1 staining was positive within glomerular deposits, supporting autoimmune secondary MN.
Evaluation for recurrent malignancy was negative. The patient was treated with pulse steroids and cyclophosphamide using a modified Ponticelli regimen. At 6 months, she achieved partial remission with creatinine improving to 1.3 mg/dL and spot urine protein-creatinine ratio decreasing to 3.7 g/g.

Discussion

EXT1 positivity with near full-house immune deposits favored autoimmune secondary MN over primary disease. Crescents in MN are rare and reflect severe immune-mediated injury. Although SS can cause secondary MN, concurrent crescents and full-house IF are highly atypical and may mimic lupus nephritis or infection-related glomerulonephritis. These presentations are linked to poor renal outcomes, including rapidly progressive glomerulonephritis and progression to ESRD. This case highlights the diagnostic value of EXT1 staining in atypical autoimmune-associated MN and the importance of considering SS in the differential diagnosis of full-house MN.