title: Helicobacter pylori genotypes in children from a population at high gastric cancer risk: no association with gastroduodenal histopathology.
abstract: OBJECTIVE
  Both bacterial and host determinants underlying differences in histopathology and clinical outcome in H. pylori pediatric infection, as compared to adults, are still poorly documented. Pediatric studies may provide important insights on H. pylori infection immunopathogenesis, particularly in high gastric cancer risk populations. The present study concerns H. pylori genotypic diversity of isolates in children from a population with high gastric cancer risk, and its association with demographic and clinical variables, including gastroduodenal endoscopic and histopathological features.
  
  
  METHODS
  A total of 119 subjects (mean age 10.3 yr, 1.5-18.0 yr) with H. pylori infection were studied. H. pylori vacA, cagA, and iceA genotypes were determined (PCR) in antral-obtained primary cultures; histopathological evaluation was performed in corpus, antrum, and duodenum biopsy specimens.
  
  
  RESULTS
  cagA-, vacA s2m2, and iceA2 were the most prevalent genotypes. No association was observed between H. pylori genotypes and subject demographic and clinical variables, with the exception of a significant association between vacA s2 genotype and lower corpus inflammation score (p< 0.03).
  
  
  CONCLUSIONS
  In this pediatric cohort, H. pylori genotype profiles were distinct from those reported in adult subjects in the same area, with a lower prevalence of the putative more virulent genotypes. Moreover, they were not associated with clinical expression of gastroduodenal disease, suggesting the potential role of host and/or environmental factors for the development of clinical disease at a later age.
authors.affiliation: Gastroenterology Unit, Paediatric Department, University Hospital Santa Maria, Lisboa, Portugal.
authors.forename: Ana Isabel Costa
authors.initials: AI
authors.lastname: Lopes
authors.forename: Ana
authors.initials: A
authors.lastname: Palha
authors.forename: Lurdes
authors.initials: L
authors.lastname: Monteiro
authors.forename: Mónica
authors.initials: M
authors.lastname: Olcastro
authors.forename: Ana
authors.initials: A
authors.lastname: Pelerito
authors.forename: Afonso
authors.initials: A
authors.lastname: Fernandes
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics*; D004386:Duodenum / Q000382:microbiology / Q000473:pathology; D016099:Endoscopy, Gastrointestinal; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D016481:Helicobacter Infections / Q000150:complications / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D011706:Pyloric Antrum / Q000382:microbiology* / Q000473:pathology; D012307:Risk Factors; D012720:Severity of Illness Index; D013274:Stomach Neoplasms / Q000150:complications* / Q000453:epidemiology / Q000473:pathology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori; C063113:ice nucleation protein