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Uchida T, Oda T. The Prevalence, Characteristics, and Putative Mechanisms of Dual Antigen-Positive Membranous Nephropathy: The Underestimated Condition. Int J Mol Sci 2024; 25:5931. [PMID: 38892120 PMCID: PMC11172907 DOI: 10.3390/ijms25115931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/18/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
Following the discovery of podocyte phospholipase A2 receptor and thrombospondin type-1 domain-containing 7A, various potential target antigens for membranous nephropathy (MN) have been reported one after another. MN target antigens have now been identified in a significant proportion of patients, and a new classification framework classifies patients with MN based on the detected antigen and associated disease phenotype. A serology-based approach that does not require a histological diagnosis for patients suspected of having MN has also been proposed. However, there have been cases in which dual positivity for MN antigens and/or corresponding antibodies has been shown. Importantly, some of them showed a transition of the affected patient's immune responses to MN antigens, suggesting that serological diagnosis changes depending on the timing of the analysis. In this review, we provide detailed information on these cases and present an overview of our recent understanding of their putative mechanisms involved in these cases. Greater awareness is required to adequately recognize and develop appropriate therapeutic strategies for this condition.
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Affiliation(s)
| | - Takashi Oda
- Department of Nephrology and Blood Purification, Kidney Disease Center, Tokyo Medical University Hachioji Medical Center, Hachioji 193-0998, Japan;
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Madden B, Singh RD, Haas M, Palma LMP, Sharma A, Vargas MJ, Gross L, Negron V, Nate T, Charlesworth MC, Theis JD, Nasr SH, Nath KA, Fervenza FC, Sethi S. Apolipoprotein E is enriched in dense deposits and is a marker for dense deposit disease in C3 glomerulopathy. Kidney Int 2024; 105:1077-1087. [PMID: 38447879 DOI: 10.1016/j.kint.2024.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 03/08/2024]
Abstract
C3 glomerulopathy (C3G) is a rare disease resulting from dysregulation of the alternative pathway of complement. C3G includes C3 glomerulonephritis (C3GN) and dense deposit disease (DDD), both of which are characterized by bright glomerular C3 staining on immunofluorescence studies. However, on electron microscopy (EM), DDD is characterized by dense osmiophilic mesangial and intramembranous deposits along the glomerular basement membranes (GBM), while the deposits of C3GN are not dense. Why the deposits appear dense in DDD and not in C3GN is not known. We performed laser microdissection (LCM) of glomeruli followed by mass spectrometry (MS) in 12 cases each of DDD, C3GN, and pretransplant kidney control biopsies. LCM/MS showed marked accumulation of complement proteins C3, C5, C6, C7, C8, C9 and complement regulating proteins CFHR5, CFHR1, and CFH in C3GN and DDD compared to controls. C3, CFH and CFHR proteins were comparable in C3GN and DDD. Yet, there were significant differences. First, there was a six-to-nine-fold increase of C5-9 in DDD compared to C3GN. Secondly, an unexpected finding was a nine-fold increase in apolipoprotein E (ApoE) in DDD compared to C3GN. Most importantly, immunohistochemical and confocal staining for ApoE mirrored the dense deposit staining in the GBM in DDD but not in C3GN or control cases. Validation studies using 31 C3G cases confirmed the diagnosis of C3GN and DDD in 80.6 % based on ApoE staining. Overall, there is a higher burden of terminal complement pathway proteins in DDD compared to C3GN. Thus, our study shows that dense deposits in DDD are enriched with ApoE compared to C3GN and control cases. Hence, ApoE staining may be used as an adjunct to EM for the diagnosis of DDD and might be valuable when EM is not available.
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Affiliation(s)
- Benjamin Madden
- Mayo Clinic Proteomics Core, Mayo Clinic, Rochester, Minnesota, USA
| | - Raman Deep Singh
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Mark Haas
- Department of Pathology & Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lilian M P Palma
- Pediatric Nephrology, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Alok Sharma
- Department of Renal Pathology & Electron Microscopy, Dr Lal Path Labs, New Delhi, India
| | - Maria J Vargas
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - LouAnn Gross
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Vivian Negron
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Torell Nate
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Jason D Theis
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Samih H Nasr
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Karl A Nath
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Fernando C Fervenza
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
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Kudose S, Stokes MB. Diagnosis of Glomerular Disease With Podocyte Infolding, Microspherical, and Microtubular Glomerular Basement Membrane Inclusions. Kidney Int Rep 2023; 8:2507-2510. [PMID: 38106589 PMCID: PMC10719634 DOI: 10.1016/j.ekir.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023] Open
Affiliation(s)
- Satoru Kudose
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
| | - M. Barry Stokes
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
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