title: Clinicopathological characteristics of M-type phospholipase A2 receptor (PLA2R)-related membranous nephropathy in Japanese.
abstract: BACKGROUND
  Recent studies have suggested that assessments of serum antibodies against M-type phospholipase A2 receptor (PLA2R) and the glomerular expression of PLA2R antigen in biopsy specimens are useful for the diagnosis of primary membranous nephropathy (MN). In this study, we assessed both of them and investigated the clinicopathological characteristics of PLA2R-related Japanese MN.
  
  
  METHODS
  We retrospectively enrolled 22 primary and 3 secondary Japanese patients whose serum samples and renal specimens were collected before treatment. According to the findings of serum antibodies and antigen in glomeruli, the primary MN patients were classified into PLA2R-related or -unrelated MN. We compared their clinicopathological findings, including IgG subclass staining, and electron microscopic findings, and evaluated the predictors of proteinuria remission.
  
  
  RESULTS
  In primary MN, 16 patients (73 %) were classified into the PLA2R-related group, and 6 patients into the PLA2R-unrelated group. There was no significant difference in baseline laboratory data and electron microscopic findings, except for eGFR and serum IgG levels. IgG4-dominant deposition was more common in the related group (63 vs. 0 %). The 10 PLA2R-related patients with dominant IgG4 deposition had a lower rate and prolonged time in remission compared with the 6 PLA2R-related patients with non-dominant IgG4 (log-rank, p = 0.032). Furthermore, dominant IgG4 deposition was an unfavorable predictor of remission by multivariable Cox proportional hazard analysis.
  
  
  CONCLUSIONS
  Assessments of both serum PLA2R antibodies and PLA2R antigen in glomeruli were more sensitive for the diagnosis of PLA2R-related MN, and among affected Japanese patients, those with dominant IgG4 deposition had worse clinical outcomes.
authors.affiliation: Division of Nephrology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Shin'ichi
authors.initials: S
authors.lastname: Akiyama
authors.affiliation: Division of Nephrology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okuyama
authors.affiliation: Division of Nephrology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsui
authors.affiliation: Division of Nephrology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Adachi
authors.affiliation: Division of Nephrology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamaya
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Maruyama
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Enyu
authors.initials: E
authors.lastname: Imai
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Matsuo
authors.affiliation: Division of Nephrology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan. h-yoko@kanazawa-med.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yokoyama
mesh_terms: D000368:Aged; D044466:Asian People; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D015433:Glomerulonephritis, Membranous / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000235:genetics; D053208:Kaplan-Meier Estimate; D007678:Kidney Glomerulus / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000209:etiology; D054507:Receptors, Phospholipase A2 / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D007074:Immunoglobulin G; C516360:PLA2R1 protein, human; D054507:Receptors, Phospholipase A2
keywords: Electron microscopic findings; IgG subclass staining; Membranous nephropathy; Phospholipase A2 receptor; Western blotting