title: Are plasma cell-rich inflammatory conditions of the oral mucosa manifestations of IgG4-related disease?
abstract: OBJECTIVE
  The aim of this study was to characterise plasma cell infiltrates, in terms of IgG4 positivity, in specific and non-specific plasma cell-rich chronic inflammatory conditions of the oral mucosa. Exploring the possibility that specific plasma cell-rich oral inflammatory conditions have association with or represent an oral manifestation of immunoglobulin G4-related disease (IgG4-RD).
  
  
  METHODS
  Ten patients with plasma cell-rich chronic inflammatory conditions of the oral mucosa were identified (seven--plasma cell mucositis and three--non-specific diffuse oral mucosal inflammation with ulceration). For each patient, the clinical record and H&E-stained sections were reviewed. Immunohistochemistry for IgG and IgG4 antibodies was performed on sections from the corresponding paraffin block, permitting calculation of the mean number of IgG4+ plasma cells per high-power field (HPF) and the IgG4+/IgG+ plasma cell ratio.
  
  
  RESULTS
  In all the cases, only one histological hallmark of IgG4-RD--a dense lymphoplasmacytic infiltrate--was seen. Review of the medical histories did not reveal any features representing other manifestations of IgG4-RD. The number of IgG4+ plasma cells exceeded 100 per HPF in half of the cases. Only two cases had an IgG4+/IgG+ plasma cell ratio of >40%; both of which were in the non-specific oral inflammatory group.
  
  
  CONCLUSIONS
  Our study suggests that plasma cell mucositis does not meet microscopic criteria for IgG4-RD. It importantly reinforces the opinion that IgG4+ plasma cells are major components of chronic inflammation in the oral cavity and the pertinence of correct contextual interpretation of histopathological features with clinical findings.
authors.affiliation: Department of Histopathology, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Hannah
authors.initials: H
authors.lastname: Cottom
authors.affiliation: Department of Oral Medicine, Leeds School of Dentistry, Leeds, Yorkshire, UK.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Mighell
authors.affiliation: Department of Histopathology, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Alec
authors.initials: A
authors.lastname: High
authors.affiliation: Department of Cellular Pathology, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: Adrian C
authors.identifier: http://orcid.org/0000-0003-2222-4104
authors.initials: AC
authors.lastname: Bateman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000276:immunology* / Q000473:pathology; D010950:Plasma Cells / Q000276:immunology* / Q000473:pathology; D013280:Stomatitis / Q000276:immunology* / Q000473:pathology
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G
keywords: IMMUNOGLOBULIN; INFLAMMATION; ORAL PATHOLOGY