title: Association of Helicobacter pylori IgA antibodies with the risk of peptic ulcer disease and gastric cancer.
abstract: OBJECTIVE
  To compare the prevalence of Helicobacter pylori (H pylori) IgG and IgA antibodies between adult subjects, with defined gastric diseases, non-defined gastric disorders and those representing the population.
  
  
  METHODS
  Data on H pylori IgG and IgA antibodies, determined by enzyme immunoassay, were analyzed in 3,252 subjects with DGD including 482 patients with gastric ulcer, 882 patients with duodenal ulcer, 1,525 patients with chronic gastritis only and 363 subjects with subsequent gastric cancer, 19,145 patients with NoDg and 4,854 POPUL subjects. The age-adjusted prevalences were calculated for 1- and 20-year age cohorts.
  
  
  RESULTS
  The prevalences of IgG antibodies were equally high (89-96%) in all 20-year age cohorts of the DGD groups, whereas the prevalences of IgG antibodies were lower and increased by age in the POPUL and NoDg groups. The prevalences of IgA antibodies were also higher in the DGD groups; among them CA (84-89%) and GU groups (78-91%) showed significantly higher prevalences than DU (68-77%) and CG patients (59-74%) (OR 2.49, 95%CI 1.86-3.34 between the GU and DU groups). In the CA, GU, and DU groups, the IgA prevalences showed only minor variation according to age, while they increased by age in the CG, POPUL, and NoDg groups (P<=0.0001). The IgA response, but not the IgG response, was associated with an increased risk of CA (OR 2.41, 95%CI 1.79-3.53) and GU (OR 2.57, 95%CI 1.95-3.39) in comparison with CG patients.
  
  
  CONCLUSIONS
  An IgA antibody response during H pylori infection is significantly more common in CA and GU patients as compared with CG patients.
authors.affiliation: Department of Bacteriology and Immunology, University of Helsinki, PO Box 21, FIN-00014 Helsinki, Finland. timo.kosunen@helsinki.fi
authors.forename: Timo U
authors.initials: TU
authors.lastname: Kosunen
authors.forename: Kari
authors.initials: K
authors.lastname: Seppala
authors.forename: Seppo
authors.initials: S
authors.lastname: Sarna
authors.forename: Arpo
authors.initials: A
authors.lastname: Aromaa
authors.forename: Paul
authors.initials: P
authors.lastname: Knekt
authors.forename: Jarmo
authors.initials: J
authors.lastname: Virtamo
authors.forename: Anniina
authors.initials: A
authors.lastname: Salomaa-Rasanen
authors.forename: Hilpi
authors.initials: H
authors.lastname: Rautelin
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology; D005387:Finland; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000276:immunology; D008875:Middle Aged; D010437:Peptic Ulcer / Q000276:immunology / Q000382:microbiology*; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000276:immunology / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G