Human leukocyte antigen class II genes and Helicobacter pylori infection: does genotype overwhelm environmental exposure?
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.
Russo
Antonio
A
Epidemiology Unit, Local Health Authority of Milan, Milan, Italy.
Maconi
Giovanni
G
Lombardo
Claudia
C
Settesoldi
Daniela
D
Ferrari
Daniela
D
Ravagnani
Fernando
F
Andreola
Salvatore
S
Pizzetti
Paolo
P
Spinelli
Pasquale
P
Bertario
Lucio
L
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
D000949:Histocompatibility Antigens Class II