dup A polymorphisms and risk of Helicobacter pylori -associated diseases

• Published in: International journal of medical microbiology Vol. 301; no. 3; pp. 225 - 228
• Main Authors: Queiroz, Dulciene M.M, Rocha, Gifone A, Rocha, Andreia M.C, Moura, Sílvia B, Saraiva, Ivan E.B, Gomes, Luciana I, Soares, Taciana F, Melo, Fabrício F, Cabral, Mônica M.D.A, Oliveira, Celso A
• Format: Journal Article
• Language: English
• Published: 2010
• Subjects: Infectious Disease; Medical Education; Gastric carcinoma; Gene polymorphisms; Helicobacter pylori; Duodenal ulcer; dupA
• ISSN: 1438-4221
• DOI: 10.1016/j.ijmm.2010.08.019

Abstract The dup A of Helicobacter pylori has been suggested as a virulence marker associated with the development of duodenal ulcer disease. However, the studies performed in different geographical areas have shown that there are variations in the prevalence of dup A and its association with H. pylori clinical outcomes. Our group did not observe associations between the presence of dup A and H. pylori clinical outcomes in Brazil. On the other hand, we observed 2 mutations in the sequence of dup A that lead to stop codons: a deletion of an adenine at position 1311 and an insertion of an adenine at position 1426 of the gene. Our aim was to evaluate associations of the presence of dup A with duodenal ulcer and gastric cancer, considering dup A-positive only those H. pylori strains that do not have the mutations in the gene sequence. We also evaluated the effect of infection with a strain carrying an intact dup A on the gastric mucosa histology and IL-8 gastric levels. Colonization with strains that had the intact dup A was negatively associated with gastric carcinoma ( p = 0.001, OR = 0.32, 95% CI = 0.16–0.66). The presence of dup A was also associated with an increased degree of antral mucosa inflammation ( p = 0.01) and with decreased corpus atrophy ( p < 0.01) as well as with increased gastric mucosa IL-8 levels ( p = 0.04). In conclusion, the infection with a H. pylori strain containing the dup A without the stop codon polymorphisms is associated with a lower risk of development of gastric carcinoma in Brazilian subjects.