Kidney Week

Abstract: FR-PO0718

Precision Nephrology: Antigen-Guided Conservative Management in Two Patients with 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

• Hanson, Valeria, University of New Mexico, Albuquerque, New Mexico, United States

Valeria Hanson, MD

• de Leoz, Josephine B., University of New Mexico, Albuquerque, New Mexico, United States

Josephine B. de Leoz, MD

• Madera Marin, Luis Norberto, University of New Mexico, Albuquerque, New Mexico, United States

Luis Norberto Madera Marin, MD

• Caza, Tiffany, Arkana Laboratories, Little Rock, Arkansas, United States

Tiffany Caza, MD, PhD

• Singh, Namita, University of New Mexico, Albuquerque, New Mexico, United States

Namita Singh, MD, MBBS, FASN

• Garcia, Pablo, University of New Mexico, Albuquerque, New Mexico, United States

Pablo Garcia, MD, MS, FASN

Introduction

Membranous nephropathy (MN) results from subepithelial deposition of antigen–antibody immune complexes. Over the past decade, novel target antigens have been identified, yet their clinical implications and optimal management remain unclear. EXT1/EXT2 positivity is classically associated with lupus-class MN, while NDNF has been linked to infection-associated forms. Here we present two cases in which antigen identification on biopsy guided a conservative, non-immunosuppressive approach.

Case Description

Case 1. A 53-year-old man with treated HIV, latent tuberculosis, and prior syphilis was referred to nephrology for nephrotic-range proteinuria (UPCR 2.9 g/g) and an eGFR of 60 mL/min/1.73m2. Serologic evaluation revealed negative ANA, ANCA, anti-dsDNA, and rheumatoid factor, with normal complement levels. Kidney biopsy demonstrated membranous glomerulopathy with positive EXT1 staining. Given the absence of clinical or serological evidence for SLE, and the past infection history, conservative management was continued. At follow-up, proteinuria improved to 1.15 g/g with stable renal function.

Case 2. A 28-year-old man with no significant past medical history presented with nephrotic syndrome (UPCR 2.8 g/g, serum albumin 0.9 g/dL, eGFR 120 mL/min/1.73m2). Workup revealed a positive treponemal antibody and RPR titer of 1:128. Kidney biopsy showed MN with positive NDNF staining, consistent with infection-associated MN. He was started on Penicillin G for treatment of syphilis, prophylactic anticoagulation for severe hypoalbuminemia, and low dose lisinopril therapy. He is scheduled to follow up with nephrology.

Discussion

We describe two cases of MN with emerging target antigens, EXT1 in the absence of lupus and NDNF in the setting of active syphilis, both managed without immunosuppressive therapy. Antigen identification on biopsy informed the decision to pursue conservative treatment, with favorable short-term outcomes in the first case. These cases highlight the growing clinical utility of antigen staining in MN and support further investigation into antigen-guided management strategies.