title: IgG4-related sialadenitis is rare: histopathological investigation of 129 cases of chronic submandibular sialadenitis.
abstract: OBJECTIVE
  The incidence of IgG4-related sialadenitis among cases of chronic sialadenitis is unknown, and so we investigated the presence of IgG4 plasma cells in 129 specimens from an archival collection of consecutive cases of chronic submandibular sialadenitis collected from 1969 to 1989 that had been previously extensively characterized.
  
  
  RESULTS
  Immunohistology revealed that only three of the 129 specimens contained areas over the threshold for IgG4-related sialadenitis of 50 IgG4 plasma cells per high-power field, and these cells were part of a non-specific chronic inflammatory infiltrate associated with ducts that had contained sialoliths. The infiltrate of IgG4 plasma cells in the series was significantly positively related to the total infiltrate of inflammatory cells, fibrosis, atrophy, lymphoid germinal centres and sialoliths.
  
  
  CONCLUSIONS
  IgG4-related sialadenitis is rare and was not found in the present series. The IgG4 plasma cells that were present in the glands were part of a non-specific chronic inflammatory infiltrate.
authors.affiliation: Unit of Oral Pathology, King's College London Dental Institute at Guy's, King's College, St Thomas' Hospitals, London, UK. john.harrison@kcl.ac.uk
authors.forename: John D
authors.initials: JD
authors.lastname: Harrison
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodriguez-Justo
mesh_terms: D002908:Chronic Disease; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D007150:Immunohistochemistry; D010950:Plasma Cells / Q000378:metabolism; D012793:Sialadenitis / Q000276:immunology / Q000473:pathology*; D013363:Submandibular Gland / Q000276:immunology / Q000473:pathology*
chemical_list: D007074:Immunoglobulin G