title: Immunoglobulin G4 immunostaining of gastric, duodenal, or colonic biopsies is not helpful for the diagnosis of autoimmune pancreatitis.
abstract: OBJECTIVE
  The aim of this study was to evaluate the specificity of the infiltration of digestive tract mucosa by immunoglobulin (Ig) G4-positive plasma cells in patients with autoimmune pancreatitis (AIP), as compared with normal or inflammatory mucosa.
  
  
  METHODS
  Plasma cell infiltration, CD138 and IgG4 immunostaining of digestive biopsies were compared in 4 groups of patients: AIP type 1 (n = 19); AIP type 2 (n = 4) with inflammatory bowel disease (IBD); IBD without pancreatic disorders (n = 20); and controls (n = 26).
  
  
  RESULTS
  With AIP type 1 versus controls, more plasma cells were present in the gastric mucosa of AIP (P = .02) without difference concerning IgG4+ plasma cells at any biopsy site. With AIP type 1 versus IBD, colonic mucosa was more often abnormal (P = .004), and more CD138 (P = .02) and IgG4 plasma cells (P = .0002) were counted in the colon biopsies of IBD. With AIP type 2 versus IBD, no difference for plasma cell and IgG4 infiltration was found.
  
  
  CONCLUSIONS
  IgG4-positive plasma cells are not more numerous in the digestive mucosa of AIP patients than in controls, but they are more abundant in the colon of IBD patients than in AIP patients.
authors.affiliation: Department of Gastroenterology and Pancreatology, Bichat Hospital, APHP, Paris, Inserm U773-CRB3, Paris-Diderot University, 92118 Clichy Cedex, France. vinciane.rebours@bjn.aphp.fr
authors.forename: Vinciane
authors.initials: V
authors.lastname: Rebours
authors.forename: Yann
authors.initials: Y
authors.lastname: Le Baleur
authors.forename: Dominique
authors.initials: D
authors.lastname: Cazals-Hatem
authors.forename: Carmen
authors.initials: C
authors.lastname: Stefanescu
authors.forename: Olivia
authors.initials: O
authors.lastname: Hentic
authors.forename: Frédérique
authors.initials: F
authors.lastname: Maire
authors.forename: Yoram
authors.initials: Y
authors.lastname: Bouhnik
authors.forename: Pierre
authors.initials: P
authors.lastname: Bedossa
authors.forename: Pascal
authors.initials: P
authors.lastname: Hammel
authors.forename: Philippe
authors.initials: P
authors.lastname: Ruszniewski
authors.forename: Philippe
authors.initials: P
authors.lastname: Lévy
authors.forename: Anne
authors.initials: A
authors.lastname: Couvelard
mesh_terms: D001327:Autoimmune Diseases / Q000175:diagnosis*; D001706:Biopsy; D019411:Clinical Laboratory Techniques / Q000379:methods*; D003106:Colon / Q000473:pathology; D004386:Duodenum / Q000473:pathology; D005753:Gastric Mucosa / Q000473:pathology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D007150:Immunohistochemistry / Q000379:methods; D007413:Intestinal Mucosa / Q000473:pathology*; D010195:Pancreatitis / Q000175:diagnosis*; D010950:Plasma Cells / Q000276:immunology; D013194:Staining and Labeling / Q000379:methods; D013270:Stomach / Q000473:pathology; D053668:Syndecan-1 / Q000032:analysis
chemical_list: D007074:Immunoglobulin G; C508241:SDC1 protein, human; D053668:Syndecan-1