title: IgG4-related renal disease: clinical and pathological characteristics.
abstract: IgG4-related disease is a recently established systemic condition. Tubulointerstitial nephritis is the most common renal manifestation. Glomerular lesions, particularly membranous glomerulonephritis, can develop simultaneously. Some patients present with serological renal dysfunction associated with elevated IgG or IgE levels and hypocomplementemia, while others are incidentally found to have abnormalities in kidneys on imaging. A majority of patients with IgG4-related kidney disease have similar lesions at other anatomical sites, which help us to suspect this condition. Serum IgG4 elevation (>135 mg/dL) is the most, although not entirely, specific marker for the diagnosis. Imaging findings varies from small nodules to bilateral diffuse abnormalities. In addition to the renal parenchyma, the renal pelvis and perirenal adipose tissue can be affected. Histological features include dense lymphoplasmacytic infiltration, storiform or "bird's eye" fibrosis (highlighted by PAM stain), and IgG4-positive plasma cell infiltration (>10 cells/high-power field and IgG4/IgG-positive cell ratio >40%). Immune complex deposition is detectable in the tubular basement membrane by immunofluorescence and/or electron microscopy. Patients usually respond well to corticosteroids, but highly active diseases may require other immunosuppressive therapies. Further investigations will be required to fully understand pathophysiology underlying this emerging condition.
authors.affiliation: Department of Diagnostic Pathology, Kochi Red Cross Hospital Kochi, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Kuroda
authors.affiliation: Department of Urology, Metabolism and Nephrology, Kochi Medical School, Kochi University Kochi, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Nao
authors.affiliation: Department of Urology, Metabolism and Nephrology, Kochi Medical School, Kochi University Kochi, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Fukuhara
authors.affiliation: Department of Urology, Metabolism and Nephrology, Kochi Medical School, Kochi University Kochi, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Karashima
authors.affiliation: Department of Urology, Metabolism and Nephrology, Kochi Medical School, Kochi University Kochi, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Department of Endocrinology, Metabolism and Nephrology, Kochi Medical School, Kochi University Kochi, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Taniguchi
authors.affiliation: Department of Diagnostic Pathology, Kobe University Graduate School of Medicine Kobe, Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Takeuchi
authors.affiliation: Department of Diagnostic Pathology, Kobe University Graduate School of Medicine Kobe, Japan.
authors.forename: Yoh
authors.initials: Y
authors.lastname: Zen
authors.affiliation: Division of Pathophisiology, Okayama University Graduate School of Health Sciences Okayama, Japan ; Department of Pathology, Okayama Graduate School of Medicine, Density, Pharmaceutical Sciences Okayama, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Anatomic Pathology, Kurashiki Central Hospital Kurashiki, Okayama, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Notohara
authors.affiliation: Department of Pathology, Okayama Graduate School of Medicine, Density, Pharmaceutical Sciences Okayama, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yoshino
mesh_terms: D001327:Autoimmune Diseases / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D015433:Glomerulonephritis, Membranous / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007668:Kidney / Q000187:drug effects / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D009395:Nephritis, Interstitial / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents
keywords: IgG4-related disease; kidney; review