title: Selective reduction of anti-Helicobacter pylori IgG subclass antibody in gastric carcinoma.
abstract: BACKGROUND
  Epidemiological studies have demonstrated strong links between Helicobacter pylori infection and gastric adenocarcinoma. Recent studies suggest that cell-mediated immunity influences the outcome of infection, including the development of gastric adenocarcinoma. The T-cell response can be characterized in terms of the secreted cytokine profile, which in turn influences the B-cell response including the balance of IgG subclass antibody.
  
  
  METHODS
  Serum anti-H. pylori IgG, IgG1 and IgG2 antibodies were studied by ELISA in subjects with benign gastric diseases, gastric dysplasia and gastric adenocarcinoma.
  
  
  RESULTS
  The distribution patterns of IgG subclass anti-H. pylori antibody varies significantly between H. pylori-linked benign and malignant disease in subjects infected with H. pylori. Significantly lower IgG2 levels were found in subjects with gastric adenocarcinoma compared with those with reflux esophagitis, chronic gastritis, gastric ulcer, and peptic ulcer, while IgG1 antibody remained at similar levels in both benign and malignant disease. A limited study of seropositive subjects with premalignant change was consistent with the fall in IgG2 antibody pre-dating malignant change, although pre-eradication results are needed to validate these data.
  
  
  CONCLUSIONS
  These studies indicate that subjects with low levels of IgG2 anti-H. pylori antibody are at risk of gastric adenocarcinoma, and that the previously described linkage between gastric adenocarcinoma and low total IgG antibody does not simply reflect reduced gastric colonization. The diagnostic value of this assay for pre-endoscopy screening is attractive.
authors.affiliation: VRI Biomedical, Newcastle Unit, New South Wales, Australia.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Ren
authors.forename: Tom
authors.initials: T
authors.lastname: Borody
authors.forename: Gerald
authors.initials: G
authors.lastname: Pang
authors.forename: Liang-Chen
authors.initials: LC
authors.lastname: Li
authors.forename: Margaret
authors.initials: M
authors.lastname: Dunkley
authors.forename: Robert
authors.initials: R
authors.lastname: Clancy
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000276:immunology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005767:Gastrointestinal Diseases / Q000097:blood / Q000276:immunology; D016481:Helicobacter Infections / Q000097:blood / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000097:blood / Q000276:immunology*
chemical_list: D007074:Immunoglobulin G