Association of peptic ulcer with increased expression of Lewis antigens but not cagA, iceA, and vacA in Helicobacter pylori isolates in an Asian population

Background-Studies in Western populations suggest that cagA, iceA, and vacA gene status in helicobacter pylori isolates is associated with increased v irulence and peptic ulcer disease. Aim-To investigate the relationship between peptic ulcer and expression of Lewis (Le) antigens as well as cagA, iceA, and vacA in H pylori isolates in Singapore.;Methods-Expression of Le antigens in H pylori isolates obtained from patients with dyspepsia was measured by enzyme Linked immunosorbent a ssay. The cagA, iceA, and vacA status was determined by polymerase chain re action. Results-Of 108 H pylori isolates, 103 (95.4%) expressed Le(x) and/or Le(y), while Le(a) and Le(b) were expressed in 23 (21.3%) and 47 (43.5%) isolates , respectively. Expression of two or more Le antigens (Le(x), Le(y), Le(a), or Le(b)) was significantly higher in H pylori isolated from ulcer patient s than in non-ulcer patients (89.6% v 73.2%, p=0.035). There were no signif icant differences in the prevalence of cagA or iceA1 in H pylori isolates f rom peptic ulcer and non-ulcer patients (86.6% v 90.2% for cagA; 70.1% v 68 .3% for iceA1), and no association of peptic ulcer with any specific vacA g enotype. Conclusions-The present study indicates that peptic ulcer disease is associ ated with increased expression of Lewis antigens but not cagA, iceA, or vac A genotype in H pylori isolates in our population. This suggests that cagA, iceA, and vacA are not universal virulence markers, and that host-pathogen interactions are important in determining clinical outcome.