title: IgG4-related kidney disease--an update.
abstract: OBJECTIVE
  IgG4-related disease (IgG4-RD) is a recently recognized systemic inflammatory disorder that can affect most organs/tissues such as sarcoidosis. The kidney is a frequently affected organ with tubulointerstitial nephritis (TIN), the representative lesion of IgG4-RD. This review focuses on the latest knowledge of IgG4-related kidney disease (IgG4-RKD).
  
  
  RESULTS
  A wide range of renal manifestations of IgG4-RD, that is TIN, membranous glomerulonephritis (MGN) and other glomerular lesions, and pyelitis, are collectively referred to as IgG4-RKD. Clinically, decreased renal function, or characteristic imaging findings such as multiple low-density lesions on contrast-enhanced computed tomography or diffuse thickening of the renal pelvic wall, are typical presenting features. Although a rapid response to corticosteroid therapy is a very important feature of IgG4-TIN, in cases in which renal function is moderately to severely decreased before therapy, only partial recovery of renal function is obtained.
  
  
  CONCLUSIONS
  TIN with characteristic imaging findings is a typical manifestation of IgG4-RKD in the interstitium, while MGN is a representative manifestation of the glomerular lesions. Although IgG4 is a central feature of IgG4-RD, the recent discovery of IgG4-negative IgG4-RD raises questions about the causative role of the IgG4 molecule in this context.
authors.affiliation: aDivision of Rheumatology, Kanazawa University Hospital, Kanazawa, Japan bDepartment of Internal Medicine, Nagaoka Red Cross Hospital, Nagaoka, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawano
authors.forename: Takako
authors.initials: T
authors.lastname: Saeki
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000150:complications / Q000175:diagnosis / Q000628:therapy*; D003952:Diagnostic Imaging; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007668:Kidney / Q000276:immunology* / Q000473:pathology*; D007674:Kidney Diseases / Q000175:diagnosis / Q000276:immunology / Q000628:therapy*; D007678:Kidney Glomerulus / Q000276:immunology*
chemical_list: D007074:Immunoglobulin G