Abstract: TH-PO0663
Detection of Known and Novel Antigens in Pediatric Phospholipase A2 Receptor-Negative Membranous Nephropathy Cohort Using Laser Microdissection and Mass Spectrometry
Session Information
- Glomerular Diseases: Immunopathogenesis and Targeted Therapeutics
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Sethi, Sanjeev, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Gowda, Diksha Mahadeva, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Haas, Mark, Cedars-Sinai, Los Angeles, California, United States
- Vivarelli, Marina, Bambino Gesù Children’s Hospital IRCCS, Rome, Italy
- Madden, Benjamin J., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Theis, Jason David, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Debiec, Hanna, Hopital Tenon, Paris, Île-de-France, France
- Vargas-Brochero, Maria J., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Diomedi-Camassei, Francesca, Bambino Gesù Children’s Hospital IRCCS, Rome, Italy
- Vrana, Julie A., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Nasr, Samih H., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Fervenza, Fernando C., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Ronco, Pierre M., Hopital Tenon, Paris, France
Background
Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults but is less well characterized in the pediatric population. In pediatric MN cases, phospholipase A2 receptor (PLA2R) is a well-described antigen. However, in many PLA2R-negative cases, the underlying antigen remains unknown. Recently, several new antigens have been identified. In this study, we aimed to investigate a pediatric MN cohort to determine whether any of these newly described antigens could be detected.
Methods
We identified 34 pediatric cases of MN from the Mayo Clinic cohort, including 12 (35.3%) PLA2R-positive and 22 (65.7%) PLA2R-negative cases. One case each was positive for EXT1/EXT2 and SEMA3B on IHC. To identify the antigens in the PLA2R-negative group, we performed laser microdissection and mass spectrometry (LMD/MS) on 12 cases of the remaining 20 cases where tissue was available. Additionally, we included 7 cases from Cedars-Sinai Hospital cohort and 13 cases from a European cohort resulting in a total of 32 PLA2R-negative cases. LMD/MS was positive when total spectral counts of an antigen was >10, and for PLA2R >20 (based on previous validation studies).
Results
LMD/MS identified an MN antigen in 11 of 12 cases from the Mayo Clinic cohort, 5 of 7 from the Cedars-Sinai cohort, and 7 of 13 from the European cohort. Thus, an MN antigen was detected in 24 (75%) out of 32 cases. The spectrum of antigens included two novel antigens- insulin-degrading enzyme (IDE) in 4 cases (12.5%) and extracellular sulfatase 1 (SULF1) in 1 case (3%). PLA2R was the most detected antigen (7/32, 22%), followed by PCSK6 (5/32, 16%) and EXT1/EXT2 (4/32, 12.5%). Less common detected antigens included NELL1 (1/32, 3%) and SEMA3B (1/32, 3%).
Conclusion
This is the largest pediatric cohort of PLA2R-negative MN cases analyzed by LMD/MS to identify MN antigens. Although no single specific antigen predominated among PLA2R-negative cases, a diverse array of known and novel antigens were detected. Notably, IDE and SULF1 were newly identified antigens in this pediatric MN cohort. Interestingly, PLA2R was detected in a subset of MN that were labeled as PLA2R-negative on kidney biopsy.