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Miyasaka R, Wada Y, Takeuchi K, Abe T, Uchitsubo R, Kawamura S, Sakurabayashi S, Naito S, Aoyama T, Shimizu A, Takeuchi Y. Lupus-like membranous nephropathy during the postpartum period expressing glomerular antigens exostosin 1/exostosin 2 and phospholipase A2 receptor: a case report. CEN Case Rep 2024; 13:318-325. [PMID: 38280123 PMCID: PMC11442721 DOI: 10.1007/s13730-023-00848-w] [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: 11/16/2023] [Accepted: 12/24/2023] [Indexed: 01/29/2024] Open
Abstract
Recently, several target antigens of membranous nephropathy (MN), such as phospholipase A2 receptor (PLA2R) and exostosin 1/exostosin 2 (EXT1/2), have been discovered. A 30-year-old woman was referred to our hospital with nephrotic range proteinuria and microscopic hematuria. She was first noted to have proteinuria before pregnancy, and her proteinuria worsened in the postpartum period. A renal biopsy showed MN. Immunofluorescence microscopy showed IgG, IgA, IgM, C3, C4, and C1q depositions in the mesangial area and glomerular capillary walls (GCWs). Regarding the IgG subclass, IgG1 and IgG3 were detected on glomeruli. Electron microscopy showed subepithelial electron-dense deposits (EDDs). EDDs were also detected in paramesangial and subendothelial areas. The diagnosis of membranous lupus nephritis (MLN) was suspected, but she did not fulfill the criteria for systemic lupus erythematosus. Neither anti-nuclear antibody nor hypocomplementemia were detected. We further evaluated glomerular EXT1/2 expressions, which were evident on GCWs. In addition, PLA2R was also detected on GCWs, although serum antibody for PLA2R was negative. She responded to immunosuppressive therapy with decreased proteinuria. In the present case, glomerular PLA2R expression implied the possibility of primary MN. However, pathological findings with a full-house staining pattern and glomerular EXT1/2 expressions were very similar to those of lupus-associated MN. Glomerular PLA2R expression appeared not to reflect immunocomplexes of PLA2R and autoantibody when considering the results for glomerular IgG subclass and the absence of serum anti-PLA2R antibody. Collectively, it is plausible that this was a case of a relatively young postpartum female who developed latent MLN rather than primary MN.
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Affiliation(s)
- Ryoma Miyasaka
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Yukihiro Wada
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan.
| | - Kazuhiro Takeuchi
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Tetsuya Abe
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Ryota Uchitsubo
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Sayumi Kawamura
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Shun Sakurabayashi
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Shokichi Naito
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Togo Aoyama
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Yasuo Takeuchi
- Department of Nephrology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
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Fu N, Yuan S, Yang G, Li H, Wang T. Concurrent glomerular PCDH7 deposits in PLA2R-associated membranous nephropathy. CEN Case Rep 2024; 13:297-301. [PMID: 38145434 PMCID: PMC11294502 DOI: 10.1007/s13730-023-00842-2] [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: 09/27/2023] [Accepted: 11/27/2023] [Indexed: 12/26/2023] Open
Abstract
The understanding of membranous nephropathy (MN) has undergone impressive advancements in the last 5 years, particularly due to identification of novel antigenic targets. M-type phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain-containing 7A (THSD7A) account for approximately 70% and 1-5% of the target antigens in primary MN, respectively. Recently, more novel/putative antigens have been identified in the remaining cases of MN that include exostosin 1/exostosin 2 (EXT1/EXT2), neural epidermal growth factor-like 1 protein (NELL-1), semaphorin 3B (SEMA3B) and protocadherin 7 (PCDH7). However, comparatively little is known about the PCDH7 among these novel antigens. As such, we herein described a unique case of positive glomerular PCDH7 deposits in PLA2R-associated MN, which may offer a deeper insight into the role of PCDH7 in MN and improve our understanding of glomerular diseases in the post-COVID era, particularly with the emerging variants.
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Affiliation(s)
- NaNa Fu
- Department of Nephrology, ShouGuang Chinese Medicine Hospital, No.3353 ShengCheng Street, ShouGuang, 262700, People's Republic of China
| | - Shuang Yuan
- Graduate School of HeBei Medical University, No.361 East ZhongShan Boulevard, Shijiazhuang, 050011, People's Republic of China
| | - Guang Yang
- TaiYuan KingMed Center for Clinical Laboratory, No.2 LongSheng Street, Taiyuan, 030000, People's Republic of China
| | - Hang Li
- Department of Nephrology, Peking Union Medical College Hospital, No.1 ShuaiFuYuan, Beijing, 100010, People's Republic of China
| | - Tao Wang
- Department of Nephrology, The First Hospital of HeBei Medical University, No.89 DongGang Road, Shijiazhuang, 050030, People's Republic of China.
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