title: Immunoblotting using multiple antigens is essential to  demonstrate the true risk of Helicobacter pylori infection  for gastric cancer.
abstract: BACKGROUND
  Enzyme-linked immunosorbent assays (ELISAs) for detection of Helicobacter pylori infection, using IgG antibodies, may significantly underestimate the association with gastric cancer.
  
  
  OBJECTIVE
  To compare associations between H. pylori and cardia (CGC) and noncardia gastric cancer (NCGC) using ELISA and immunoblotting and determine the effect of atrophic gastritis on detection.
  
  
  METHODS
  Nested case-control study within the Melbourne Collaborative Cohort Study. Helicobacter pylori antibodies were detected in subjects with CGC (n = 18), NCGC (n = 34) and controls (n = 69 and 134 respectively) using ELISA (pylori DTect) and immunoblot (Helicoblot 2.1). Pepsinogen I levels were measured using ELISA.
  
  
  RESULTS
  Using ELISA, H. pylori-positivity in the CGC group was 33% vs. 35% in controls [odds ratio (OR = 0.9, 95% CI: 0.3-2.7)], while that in the NCGC group was 79% vs. 63% in controls [OR = 2.3 (95% CI: 0.9-5.8)]. Based on immunoblotting, H. pylori-positivity in the CGC group was 44% vs. 39% in their controls [OR = 1.2 (95% CI: 0.4-3.4)], while that in the NCGC group was 94% vs. 63% in controls [OR = 10.6 (95% CI: 2.4-47.4)]. Pepsinogen I levels in the NCGC cases and controls showed the lowest median level (4 ng/mL) to be in subjects negative by ELISA but positive by immunoblotting.
  
  
  CONCLUSIONS
  Immunoblotting improves the accuracy of H. pylori studies involving gastric cancer.
authors.affiliation: The School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Mitchell
authors.forename: D R
authors.initials: DR
authors.lastname: English
authors.forename: F
authors.initials: F
authors.lastname: Elliott
authors.forename: M
authors.initials: M
authors.lastname: Gengos
authors.forename: J H
authors.initials: JH
authors.lastname: Barrett
authors.forename: G G
authors.initials: GG
authors.lastname: Giles
authors.forename: D
authors.initials: D
authors.lastname: Forman
mesh_terms: D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D016481:Helicobacter Infections / Q000150:complications; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020116:Pepsinogen A / Q000097:blood; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D013274:Stomach Neoplasms / Q000382:microbiology*
chemical_list: D000942:Antigens, Bacterial; D015415:Biomarkers; D020116:Pepsinogen A