Association of cagA and iceA genotypes with Helicobacter pylori related diseases in Xi'an area

AIM: To study the impact of cagA, iceA genes and their synergy on the outcome of H pylori infec t ion so as to explore the dominant genotypes of H pylori that induce certain diseases in Xi'an area. METHODS: One hundred and one H pylori-positive specimens from the patients after gastroscopy were preliminarily selected using the rapid urease test (RUT) and 91 eligible cases were chosen from them using the method of polymerase chain reaction (PCR) to amplify ureC. The subtypes of cagA, iceA genes were detected by PCR and agarose gel electrophoresis. Relationship between different combinations of genotypes and disease was analyzed using χ² test and Fisher exact test. RESULTS: The cagA-positive rate was 79.1%, and the overall detection rate of iceA was 75.82%, in which the detection rate of iceA1 was 50.5% and that of iceA2 was 38.5%. The positive rate of cagA⁺/iceA1⁺ was higher than that of other groups. Each gene alone or genes in different combinations didn't show any statistical significance in clinical outcomes. The relevance existed in iceA and cagA. 229 bp, 334 bp, 439 bp, 549 bp and 229 bp+334 bp fragments of the genes were found in iceA2. CONCLUSION: cagA ⁺/iceA1⁺ is the dominant genotype of H pylori in Xi'an area. Neither a single gene nor the combination of cagA, iceA1, iceA2 are helpful in predicting the clinical outcome of H pylori infection. We may find synergy with the iceA and cagA. iceA2 shows greater variability in Xi'an area.