title: Comparison of the virulence markers of Helicobacter pylori and their associated diseases in patients from Pakistan and Afghanistan.
abstract: OBJECTIVE
  Helicobacter pylori is a Gram-negative bacteria, which is associated with development of gastroduodenal diseases. The prevalence of H. pylori and the virulence markers cytotoxin-associated gene A and E (cagA, cagE) and vacuolating-associated cytotoxin gene (vacA) alleles varies in different parts of the world. H. pylori virulence markers cagA, cagE, and vacA alleles in local and Afghan nationals with H. pylori-associated gastroduodenal diseases were studied.
  
  
  METHODS
  Two hundred and ten patients with upper gastrointestinal symptoms and positive for H. pylori by the urease test and histology were included. One hundred and nineteen were local nationals and 91 were Afghans. The cagA, cagE, and vacA allelic status was determined by polymerase chain reaction.
  
  
  RESULTS
  The nonulcer dyspepsia (NUD) was common in the Afghan patients (P = 0.025). In Afghan H. pylori strains, cagA was positive in 14 (82%) with gastric carcinoma (GC) compared with 29 (45%) with NUD (P = 0.006), whereas cagE was positive in 11 (65%) with GC and 4 (67%) with duodenal ulcer (DU) compared with 12 (18%) with NUD (P < 0.001 and 0.021, respectively). The vacA s1a/b1was positive in 10 (59%) of GC compared with 20 (31%) in NUD (P = 0.033). In Pakistani strains, cagE was positive in 12 (60%) with GC, 7 (58%) with GU, 12 (60%) with DU compared with 11 (16%) with NUD (P < 0.001, 0.004, and < 0.001, respectively). In Pakistani strains, cagA/s1a/m1 was 39 (33%) compared with Afghans in 17 (19%) (P = 0.022). Moderate to severe mucosal inflammation was present in 51 (43%) Pakistani patients compared with 26 (28%) (P = 0.033) in Afghans. It was also associated with grade 1 lymphoid aggregate development in Pakistani patients 67 (56%) compared with 36 (40%) (P = 0.016) in Afghans.
  
  
  CONCLUSIONS
  Distribution of H. pylori virulence marker cagE with DU was similar in Afghan and Pakistan H. pylori strains. Chronic active inflammation was significantly associated with Pakistani H. pylori strains.
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Javed
authors.initials: J
authors.lastname: Yakoob
authors.forename: Zaigham
authors.initials: Z
authors.lastname: Abbas
authors.forename: Wasim
authors.initials: W
authors.lastname: Jafri
authors.forename: Muhammad W
authors.initials: MW
authors.lastname: Usman
authors.forename: Fatima
authors.initials: F
authors.lastname: Jafri
authors.forename: Safia
authors.initials: S
authors.lastname: Awan
mesh_terms: D000328:Adult; D000346:Afghanistan / Q000453:epidemiology; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D015331:Cohort Studies; D004379:Duodenal Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D004381:Duodenal Ulcer / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D005838:Genotype; D016481:Helicobacter Infections / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D018570:Risk Assessment; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D013276:Stomach Ulcer / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C103937:PicB protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori
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