The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis

Introduction: Pauci-immune crescentic glomerulonephritis (GN) is nearly synonymous with antineutrophil cytoplasmic antibody (ANCA)–associated disease. Cases with immune complex deposition create a diagnostic conundrum leading to suspicion for concurrent infection or autoimmune disease. Small case se...

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Main Authors: Rachelle Gietzen, Tiffany N. Caza, Alejandro Best-Rocha, Christopher P. Larsen
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Kidney International Reports
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Online Access:http://www.sciencedirect.com/science/article/pii/S2468024925001287
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author Rachelle Gietzen
Tiffany N. Caza
Alejandro Best-Rocha
Christopher P. Larsen
author_facet Rachelle Gietzen
Tiffany N. Caza
Alejandro Best-Rocha
Christopher P. Larsen
author_sort Rachelle Gietzen
collection DOAJ
description Introduction: Pauci-immune crescentic glomerulonephritis (GN) is nearly synonymous with antineutrophil cytoplasmic antibody (ANCA)–associated disease. Cases with immune complex deposition create a diagnostic conundrum leading to suspicion for concurrent infection or autoimmune disease. Small case series have demonstrated myeloperoxidase (MPO) in the immune deposits in patients with membranous nephropathy (MN) and ANCA-associated disease. However, the specificity of MPO staining to characterize immune deposits in crescentic GN has not been thoroughly evaluated. Methods: We performed MPO immunostaining of 143 kidney biopsies, including pauci-immune crescentic GN (n = 15), ANCA with immune-complex crescentic GN (n = 20), MN without crescents (n = 24), endocarditis-associated crescentic GN (n = 25), hydralazine-associated crescentic GN (n = 11), and concurrent crescentic GN and MN without phospholipase A2 receptor (PLA2R) (n = 38) and with PLA2R (n = 10). MPO immunohistochemistry (IHC) was evaluated for positivity, character, and location of MPO immune deposits by 4 blinded pathologists. Results: In patients with dual crescentic GN and MN without PLA2R, 84.2% were MPO-IHC positive. Crescentic GN with mesangial IgG was MPO-IHC positive in 40%. Crescentic GN related to hydralazine exposure was MPO-IHC positive in 72.7%. All cases with pauci-immune crescentic GN, endocarditis-associated cases, and MN cases with known antigens were negative for MPO. Conclusion: Our study demonstrated that glomerular immune deposits in patients with crescentic GN with positive MPO serology demonstrated MPO positivity in the pattern of immune deposits in the majority of cases. Glomerular immune complexes in patients with MPO-positive crescentic GN therefore represent MPO-IgG immune complexes and should be thought of as one disease rather than a second disease process.
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spelling doaj-art-6d45d0b298a146ebb34ee3a35c68e94c2025-08-20T02:33:35ZengElsevierKidney International Reports2468-02492025-05-011051460146710.1016/j.ekir.2025.03.001The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic GlomerulonephritisRachelle Gietzen0Tiffany N. Caza1Alejandro Best-Rocha2Christopher P. Larsen3Arkana Laboratories, Little Rock, Arkansas, USA; Correspondence: Rachelle Gietzen, Arkana Laboratories, Little Rock, Arkansas, USA.Arkana Laboratories, Little Rock, Arkansas, USAArkana Laboratories, Little Rock, Arkansas, USAArkana Laboratories, Little Rock, Arkansas, USAIntroduction: Pauci-immune crescentic glomerulonephritis (GN) is nearly synonymous with antineutrophil cytoplasmic antibody (ANCA)–associated disease. Cases with immune complex deposition create a diagnostic conundrum leading to suspicion for concurrent infection or autoimmune disease. Small case series have demonstrated myeloperoxidase (MPO) in the immune deposits in patients with membranous nephropathy (MN) and ANCA-associated disease. However, the specificity of MPO staining to characterize immune deposits in crescentic GN has not been thoroughly evaluated. Methods: We performed MPO immunostaining of 143 kidney biopsies, including pauci-immune crescentic GN (n = 15), ANCA with immune-complex crescentic GN (n = 20), MN without crescents (n = 24), endocarditis-associated crescentic GN (n = 25), hydralazine-associated crescentic GN (n = 11), and concurrent crescentic GN and MN without phospholipase A2 receptor (PLA2R) (n = 38) and with PLA2R (n = 10). MPO immunohistochemistry (IHC) was evaluated for positivity, character, and location of MPO immune deposits by 4 blinded pathologists. Results: In patients with dual crescentic GN and MN without PLA2R, 84.2% were MPO-IHC positive. Crescentic GN with mesangial IgG was MPO-IHC positive in 40%. Crescentic GN related to hydralazine exposure was MPO-IHC positive in 72.7%. All cases with pauci-immune crescentic GN, endocarditis-associated cases, and MN cases with known antigens were negative for MPO. Conclusion: Our study demonstrated that glomerular immune deposits in patients with crescentic GN with positive MPO serology demonstrated MPO positivity in the pattern of immune deposits in the majority of cases. Glomerular immune complexes in patients with MPO-positive crescentic GN therefore represent MPO-IgG immune complexes and should be thought of as one disease rather than a second disease process.http://www.sciencedirect.com/science/article/pii/S2468024925001287crescentic glomerulonephritismembranous nephropathymyeloperoxidase
spellingShingle Rachelle Gietzen
Tiffany N. Caza
Alejandro Best-Rocha
Christopher P. Larsen
The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis
Kidney International Reports
crescentic glomerulonephritis
membranous nephropathy
myeloperoxidase
title The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis
title_full The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis
title_fullStr The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis
title_full_unstemmed The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis
title_short The Utility of Myeloperoxidase Immunostaining to Characterize Immune Deposits in Patients With Crescentic Glomerulonephritis
title_sort utility of myeloperoxidase immunostaining to characterize immune deposits in patients with crescentic glomerulonephritis
topic crescentic glomerulonephritis
membranous nephropathy
myeloperoxidase
url http://www.sciencedirect.com/science/article/pii/S2468024925001287
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