title: Association of gastroduodenal disease phenotype with ABO blood group and Helicobacter pylori virulence-specific serotypes.
abstract: OBJECTIVE
  To investigate the prevalence of Helicobacter pylori infection in Lebanon and the association between virulence factors (cytotoxin-associated gene A and vacuolating cytotoxin gene A), ABO blood groups, and disease phenotype.
  
  
  METHODS
  One hundred and thirty symptomatic patients with H. pylori-associated endoscopic findings and 104 healthy male donors (age range 18-55) were evaluated. Both, patients and donors underwent ABO blood typing and Western blot for cytotoxin-associated gene A and vacuolating cytotoxin gene A.
  
  
  RESULTS
  The prevalence of H. pylori infection in healthy donors is 68.3%. Type I (cytotoxin-associated gene A- and vacuolating cytotoxin gene A-positive) was the predominant phenotype in all groups, though significantly less common in the asymptomatic population (46.5%) than in patients with benign disease (71.4%, p<0.01) or malignancy (71.6%, p<0.05). Type II (cytotoxin-associated gene A- and vacuolating cytotoxin gene A-negative) and vacuolating cytotoxin gene A-only strains were more common in the asymptomatic cohort. Overall, 35.2% of asymptomatic individuals and 10.8% of patients with benign disease were cytotoxin-associated gene A-negative (p<0.01). There was no significant association between immunoserotypes, ABO groups or benign gastroduodenal disease. All gastric malignancies (lymphoma and adenocarcinoma) were cytotoxin-associated gene A-positive but this was not significantly different from patients with benign disease. We found a higher prevalence of blood group A in patients with gastric malignancy than in the general population [47.6% versus 25%, p=0.037; RR=2.73 (1.04-7.16; 95% CI)].
  
  
  CONCLUSIONS
  The seroprevalence of H. pylori is moderately high in Lebanon. Phenotypic classification identifies a higher prevalence of Type I in symptomatic patients. A significant relationship between infection with a cytotoxin-associated gene A-positive strain in blood type A patients and the risk of gastric malignancy was noted.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, American University of Beirut Medical Center, P.O. Box 11-0236, Beirut 1107 2020, Lebanon. as08@aub.edu.lb
authors.forename: A I
authors.initials: AI
authors.lastname: Sharara
authors.forename: H
authors.initials: H
authors.lastname: Abdul-Baki
authors.forename: I
authors.initials: I
authors.lastname: ElHajj
authors.forename: N
authors.initials: N
authors.lastname: Kreidieh
authors.forename: E M
authors.initials: EM
authors.lastname: Kfoury Baz
mesh_terms: D000017:ABO Blood-Group System; D000230:Adenocarcinoma / Q000097:blood* / Q000382:microbiology; D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000097:blood; D015153:Blotting, Western; D016022:Case-Control Studies; D005260:Female; D016481:Helicobacter Infections / Q000097:blood* / Q000453:epidemiology; D016480:Helicobacter pylori / Q000145:classification / Q000472:pathogenicity*; D006801:Humans; D007861:Lebanon / Q000453:epidemiology; D008223:Lymphoma / Q000097:blood / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000097:blood* / Q000382:microbiology; D010641:Phenotype; D013272:Stomach Diseases / Q000097:blood / Q000382:microbiology
chemical_list: D000017:ABO Blood-Group System; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori