ABO blood groups and Helicobacter pylori cagA infection: evidence of an association

diseases resulting from helicobacter pylori infection appear to be dependent on a host of genetic traits and virulence factors possessed by this microorganism. this paper aimed to investigate the association between the abo histo-blood groups and h. pylori caga infections. genomic dna samples (n = 110) of gastric biopsies obtained from patients with endoscopic diagnosis of peptic ulcers (n = 25) and chronic active gastritis (n = 85) were analyzed by pcr using specific primers for the caga gene. of the samples, 66.4% (n = 73) tested positive and 33.6% (n = 37) negative for the gene. the caga strain was predominant in peptic ulcers (n = 21; 84.0%) compared with chronic active gastritis (n = 52; 61.2%) (p = 0.05; or 3.332; 95% ci: 1.050-10.576). additionally, the caga strain was prevalent in the type o blood (48/63; 76.2%) compared with other abo phenotypes (25/47; 53.2%) (p = 0.01; or 2.816; 95% ci: 1.246-6.364). these results suggest that h. pylori caga infection is associated with the o blood group in brazilian patients suffering from chronic active gastritis and peptic ulcers.