Urine IgG4 Is Similar Between Primary Membranous Glomerulopathy (pMGN) Wit Stage 1-2 Deposits and That With Stage 3-4 Deposits

Document Type

Conference Proceeding

Publication Date

11-2025

Publication Title

American Journal of Clinical Pathology

Abstract

Introduction/Objective: IgG4 is closely related to PLA2R in the serum of patients with pMGN. Our recent study indicated that PLA2R remained positive in different stages of pMGN (staged 1 to 4 by electron microscopy [EM]), while IgG4 stained positively in stage 1-2 but faded away in stages 3-4. This pilot study aims to determine whether urine IgG4 levels in stage 3-4 are comparable to those in stage 1-2 pMGN. Methods/Case Report: Patient #1 had nephrotic range proteinuria (urine protein/creatinine ratio [UPCR] up to 7.55 mg/mg). His transplant renal biopsy showed de novo pMGN with positive stains for PLA2R and IgG4, and stage 1 subepithelial deposits by EM. Patient #2 showed nephrotic range proteinuria (UPRC at 4.96 mg/mg) and a transplant renal biopsy with recurrent pMGN and positive PLA2R but focal/weak IgG4 staining; EM showed stage 3-4 intramembranous vacuoles. Urine IgG4 levels were then measured in the two transplant patients. Patients #1 and #2 had comparable levels of IgG4, 0.415 mg/ dl and 0.423 mg/dl per unit urine protein, respectively. Results: NA Conclusion: Our pilot data supports the notion that EM staging (either 1-2 or 3-4) of immune complex deposits in pMGN only represents evolving stages of the deposits but does not predict the levels of proteinuria.

Volume

164

Issue

Suppl 1

First Page

S164

Comments

American Society for Clinical Pathology (ASCP) Annual Meeting, November 17-20, 2025, Atlanta, GA

Last Page

S164

DOI

10.1093/ajcp/aqaf121.393

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