title: IgG4-Related Tubulointerstitial Nephritis.
abstract: Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a fibroinflammatory disorder that can involve nearly any organ. The disorder has increasingly become known as a distinct clinical entity during the last decade. IgG4-related tubulointerstitial nephritis (IgG4-TIN) is the most common manifestation of IgG4-RD in the kidney. Many patients with IgG4-TIN are diagnosed after IgG4-RD has been recognized in other organ systems, but the kidney may also be the first or only site involved. The presenting clinical features of IgG4-TIN are most commonly kidney insufficiency, kidney mass lesion(s), or both. On biopsy, IgG4-TIN shows a dense lymphoplasmacytic infiltrate, increased IgG4+ plasma cells, storiform fibrosis, and often tubular basement membrane immune complex deposits. Elevation of serum IgG4 often accompanies IgG4-RD; however, it is not specific in reaching the diagnosis. Like IgG4-RD in other organs, IgG4-TIN characteristically responds promptly to steroids, although there is a high relapse rate on discontinuation of immunosuppression. The pathogenesis of IgG4-RD is not understood.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
authors.forename: Pingchuan
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN. Electronic address: Cornell.Lynn@mayo.edu.
authors.forename: Lynn D
authors.initials: LD
authors.lastname: Cornell
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008279:Magnetic Resonance Imaging; D009395:Nephritis, Interstitial / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D007074:Immunoglobulin G
keywords: IgG4-related disease; Immune complex; Interstitial nephritis; Plasma cell