Abstract: TH-PO0747
Association Between Podocyte IgG and Circulating Antinephrin in Diffuse Podocytopathy in Adults
Session Information
- Glomerular Histopathology: Evolving Insights
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Wang, Qiyu, Brigham and Women's Hospital, Boston, Massachusetts, United States
- Ghasemi, Maryam, Brigham and Women's Hospital, Boston, Massachusetts, United States
- Watts, Andrew James Baxter, VA Boston Healthcare System, West Roxbury, Massachusetts, United States
- Mount, David B., Brigham and Women's Hospital, Boston, Massachusetts, United States
- Weins, Astrid, Brigham and Women's Hospital, Boston, Massachusetts, United States
Background
Circulating anti-nephrin antibody (Ab) has been detected in 40~60% adult patients (pts) with diffuse podocytopathy (DP). Punctate podocyte IgG, a tissue marker for anti-nephrin Ab, was observed in ~60% of DP at our institution. We evaluated the association between tissue and serological markers of anti-nephrin mediated injury and between circulating Ab and disease activity.
Methods
We reviewed biopsies of newly diagnosed DP with concurrent serum Ab sampling within 15 days from 2018-2025 at our institution. Serum Ab was tested by anti-nephrin ELISA as previously described. A threshold of 139U/mL was used to define positivity based on healthy controls. Podocyte IgG was adjudicated by 2 pathologists by routine immunofluorescence (IF); microscopy for IgG-nephrin colocalization was performed in select cases.
Results
Of 16 pts 15 had nephrotic syndrome at biopsy and 1 nephrotic-range proteinuria. Median time between biopsy and serum sampling was 0 days (range -7—15) (Table 1). All pts (8/8) with +podocyte IgG and 38% (3/8) with -podocyte IgG were positive (pos) for serum Ab (Figure 1). Of the 3 pts with discordant biopsy-serum testing, IF with IgG-nephrin dual staining was pos in 2, and negative (neg) in 1. 8 serologically pos pts underwent follow-up testing at disease remission: 6/8 (75%) had neg serum anti-nephrin, while 2/8 (25%) remained pos.
Conclusion
Podocyte IgG correlates with pos serum Ab in DP during active disease in majority of pts. Reflex dual IgG-nephrin staining increased detection and may serve as a sensitive adjunct diagnostic. Persistent pos serum anti-nephrin in the 2 pts at remission was unexplained and requires further study.
Funding
- Private Foundation Support