title: Human leukocyte antigen class II genes and Helicobacter pylori infection: does genotype overwhelm environmental exposure?
abstract: OBJECTIVE
  We investigated associations between human leukocyte antigen class II genes, environmental exposures, and Helicobacter pylori infection.
  
  
  METHODS
  Sixty-eight subjects with histologically confirmed H. pylori and intestinal metaplasia (cases) and 70 healthy subjects without H. pylori (controls) matched for age, sex, and year of birth were included in this study. All patients answered a detailed questionnaire designed to collect sociodemographic characteristics, smoking, alcohol drinking, and dietary habits. Human leukocyte antigen class II genes were typed with genomic DNA. The cytotoxins CagA and VacA were investigated with serology. Odds ratios and corresponding 95% confidence intervals were estimated from multivariate conditional logistic regression. Multiple correspondence analysis was used to represent the interrelationships of a multiple contingency table.
  
  
  RESULTS
  Human leukocyte antigen DRB1, DQA1, and DQB1 genotypes were not significantly associated with H. pylori infection and intestinal metaplasia. No significant association with blood group or Lewis antigen system was found. However, multiple correspondence analysis clearly associated H. pylori with environmental exposure: the control group largely consumed olive oil, fresh fruits, and vegetables and histories of never or formerly smoking and the case group (those positive for H. pylori and metaplasia) largely consumed eggs, meat and butter and had histories of smoking cigarettes.
  
  
  CONCLUSIONS
  These findings suggested that H. pylori infection is not influenced by a genetic compound and confirmed the relevance of environmental exposure.
authors.affiliation: Epidemiology Unit, Local Health Authority of Milan, Milan, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Russo
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maconi
authors.forename: Claudia
authors.initials: C
authors.lastname: Lombardo
authors.forename: Daniela
authors.initials: D
authors.lastname: Settesoldi
authors.forename: Daniela
authors.initials: D
authors.lastname: Ferrari
authors.forename: Fernando
authors.initials: F
authors.lastname: Ravagnani
authors.forename: Salvatore
authors.initials: S
authors.lastname: Andreola
authors.forename: Paolo
authors.initials: P
authors.lastname: Pizzetti
authors.forename: Pasquale
authors.initials: P
authors.lastname: Spinelli
authors.forename: Lucio
authors.initials: L
authors.lastname: Bertario
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004032:Diet; D005260:Female; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D016480:Helicobacter pylori / Q000254:growth & development / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D007422:Intestines / Q000473:pathology; D008019:Life Style; D016015:Logistic Models; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D012907:Smoking; D011795:Surveys and Questionnaires
chemical_list: D000949:Histocompatibility Antigens Class II