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Title: [Helicobacter pylori genotypes and their association with host's immune response]. Author: Garza-González E, Pérez-Pérez GI, Tijerina-Menchaca R, Maldonado-Garza HJ, Bosques-Padilla FJ. Journal: Rev Gastroenterol Mex; 2002; 67(3):155-60. PubMed ID: 12653051. Abstract: BACKGROUND DATA: The study of Helicobacter pylori phenotypes and genotypes is mainly focused on two groups of putative bacterial virulence factors: the cag pathogenicity island (PAI), for which CagA is a marker, and the vacuolating cytotoxin VacA. Several studies have shown the clinical relevance of the determination of IgG anti-CagA antibodies. OBJECTIVE: To assess the prevalence of vacA and cagA genotypes of H. pylori and the association with IgG anti-CagA antibodies in symptomatic patients. METHODS: We studied 50 patients (mean age 53 years, range 15-92). PCR amplification of the vacA s and m regions was performed using the primers described (J Biol Chem 1995; 270: 17771). For cagA PCR, primers described by Rugge et al. were used (Cancer 1999; 85: 2506) and determination of IgG anti-CagA antibodies was done according to the method described by Blaser and Perez (Cancer Res 1995; 55: 2111). RESULTS: All 50 patients studied were positive for H. pylori. Of the 50 H. pylori strains, 7 (14%) were isolated from patients with peptic ulcer disease and 43 (86%) from patients with non-ulcer dyspepsia. The most frequent vacA genotype was s2/m2, associated with cagA-H. pylori strains (p < 0.01). Presence of cagA+ H. pylori strains correlated with the presence of IgG antibodies (Kappa = 0.680). Determination of IgG anti-CagA antibodies showed a sensitivity of 77.4%, specificity of 94.7%, positive value of 96% and negative predictive value of 72%. CONCLUSIONS: The most frequent H. pylori genotype found in northeastern Mexico was vacA s2/m2, cagA-. The presence of this genotype correlated with the clinical presentations observed in these patients. In addition, CagA serology showed a great specificity and good sensitivity that allow us to use this assay to assess the prevalence of CagA+ strains in Mexico.[Abstract] [Full Text] [Related] [New Search]