Differences in antibody levels to H. pylori virulence factors VacA and CagA among African Americans and whites in the Southeast USA.

PURPOSE: Helicobacter pylori (H. pylori) is the leading cause of gastric cancer. High antibody levels to H. pylori virulence factors Vacuolating cytotoxin A (VacA) and Cytotoxin-associated gene A (CagA) have been suggested as gastric cancer risk markers. In the USA, H. pylori sero-prevalence is twofold higher in African Americans compared to whites. We sought to assess whether African Americans also exhibit higher antibody levels to VacA and CagA. METHODS: Antibody responses to H. pylori proteins were measured by multiplex serology in 686 African Americans and whites of the Southern Community Cohort Study. Among VacA- and CagA-seropositives, we analyzed the association of race with antibody level using logistic regression models to produce odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Sero-positive African Americans had significantly higher mean antibody levels to both VacA and CagA, which resulted in increased odds for the highest quartile of antibody levels compared to sero-positive whites (VacA, OR: 6.08; 95% CI 3.41, 10.86; CagA, OR: 3.77; 95% CI 1.61, 8.84). CONCLUSION: Our findings support future studies to assess the association of differential antibody responses by race with risk of gastric cancer in the USA, which could then aid in developing targeted H. pylori eradication strategies.