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Abstract: TH-PO451

Childhood Membranous Nephropathy: A Histopathologic Analysis of 118 Cases

Session Information

Category: Glomerular Diseases

  • 1302 Glomerular Diseases: Immunology and Inflammation

Authors

  • Caza, Tiffany, Arkana Laboratories, Little Rock, Arkansas, United States
  • Larsen, Christopher Patrick, Arkana Laboratories, Little Rock, Arkansas, United States
Background

Membranous nephropathy (MN) is a rare etiology of nephrotic syndrome in children, accounting for less than 5% of renal biopsies. Unlike MN in adults, where the majority of cases are positive for phospholipase A2 receptor (PLA2R), PLA2R positivity is less frequent and the antigen is unknown in a greater proportion of cases. We present the largest case series of pediatric MN to date with a total of 118 patients.

Methods

Cases of MN diagnosed in individuals ≤18 years of age were identified from a biopsy database. Light, immunofluorescence, and electron microscopy findings were reviewed. Antigenic subtyping was performed through immunostaining for phospholipase A2 receptor (PLA2R), thrombospondin type 1-domain containing 7A (THSD7A), exostosin 1/2 (EXT), neural epidermal growth factor-like 1 (NELL1), and semaphorin 3B (SEMA3B).

Results

A total of 118 cases of pediatric MN were identified over a 16-year period (2006-2022). The mean age of patients was 14.7 ± 2.6 years and included 47 males and 71 females. The majority of cases did not show significant chronicity, with a mean global glomerulosclerosis of 4.3 ± 10.0% and moderate or severe interstitial fibrosis in only 5.1%. Immunofluorescence studies showed 31.4% with IgA deposits, 100% IgG, 30.5% IgM, 78.8% C3, and 15.3% C1q. Mesangial deposits were seen in 62.7% and tubular basement membrane deposits in 9.3% of cases. Antigen types included 34.7% PLA2R, 0.8% THSD7A, 23.7% EXT1/2, 3.4% NELL1, 5.0% SEMA3B, and 32.2% of unknown antigen type.

Conclusion

Pediatric MN has a female predominance, often is without significant chronic injury, and has a high frequency of cases of unknown antigen type. There is a higher proportion of EXT1/2-positive cases than reported in adults.

Funding

  • NIDDK Support