title: Distribution of Helicobacter pylori virulence markers in patients with gastroduodenal diseases in Pakistan.
abstract: BACKGROUND
  Helicobacter pylori (H. pylori) infection is known to be associated with a spectrum of gastroduodenal diseases. We studied the association of H. pylori virulence markers cytotoxin-associated gene (cagA) and vacuolating associated cytotoxin gene (vacA) alleles in patients with non ulcer dyspepsia (NUD), gastric ulcer (GU), gastric carcinoma (GC) and duodenal ulcer (DU).
  
  
  METHODS
  H. pylori infection established by both rapid urease test and histology were studied. The cagA and vacA allelic status was determined by polymerase chain reaction (PCR). Sequencing of vacA i1 and i2 PCR product was carried out.
  
  
  RESULTS
  Two hundred and twenty-four patients were included, 141 (63%) were males with a mean age of 45 +/- 16, range 16-83 years. The virulence marker cagA was associated with GU in 20(63%) (p = 0.04), DU in 23(72%) (p = 0.003) and GC in 29(73%) (p = 0.001) compared to NUD in 51(42%). VacA s1am1 was associated with GU in 23(72%) (p = 0.001), DU in 17(53%) (p < 0.001) and GC in 23(58%) (p = 0.003) compared to NUD in 38(32%) while vacA s1bm1 was also associated with GU in 9(28%) (p = 0.001), DU in 12(37%) (p < 0.001) and GC 11(28%) (p < 0.001) compared to NUD in 13(11%), respectively. The diagnoses of GU in 21(66%), DU in 16(50%), GC in 20(50%) and NUD in 50(42%) were associated with moderately active chronic inflammation. CagA in 55(45%) (p = 0.037), vacA s1am1 in 51(51%) (P < 0.001), s1bm1 in 25(56%) (p = 0.002), s1am2 32(30%) (p < 0.001) and s1bm2 29(69%) (p = 0.004) were also associated with moderately active chronic inflammation.
  
  
  CONCLUSIONS
  CagA was negative in majority of NUD patients with H. pylori infection. However, cagA was associated with peptic ulcer and GC. VacA allele's s1am1 and s1bm1 were associated with H. pylori associated diseases and inflammation.
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan. yakoobjaved@hotmail.com
authors.forename: Javed
authors.initials: J
authors.lastname: Yakoob
authors.forename: Shahab
authors.initials: S
authors.lastname: Abid
authors.forename: Zaigham
authors.initials: Z
authors.lastname: Abbas
authors.forename: Wasim
authors.initials: W
authors.lastname: Jafri
authors.forename: Zubair
authors.initials: Z
authors.lastname: Ahmad
authors.forename: Rashida
authors.initials: R
authors.lastname: Ahmed
authors.forename: Muhammad
authors.initials: M
authors.lastname: Islam
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D015415:Biomarkers / Q000032:analysis*; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology* / Q000378:metabolism / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology* / Q000378:metabolism / Q000382:microbiology; D016480:Helicobacter pylori / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D010154:Pakistan / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D014774:Virulence; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D015415:Biomarkers; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori