Significance of cagA Gane in Gastric Biopsy Specimens of Normal Subject Without Gastroscopic Abnormality

Kim, Hae Ryun; Yang, Suk Kyun; Hong, Weon Seon; Jung, Hwoon Yong; Nam, Seung Woo; Park, Ju Sang; Kang, Gyeong Hoon; Youn, Kwang Hee; Lee, Mi Hun; Koh, Jin Kyu

Abstract

Background/Airns: It becomes clear that clinical manifestation of H. pylori infection has marked diversity mainly due to the strain diversity of H. pylori and host susceptibility. Many attempts have been made to identify the pathogenic strains of H. pylori, and have shown that the strain with the gene coding for cagA may be a pathogenic strain. To determine the role of cagA gene in the developrnent of gastroduodenal diseases, it is important to test cagA gene in gastric tissues without gross abwrmality.
METHODS
In a total of forty-seven persons without abnormal gastroscopic findings, the prevalence of H. pylori was determined by polymerase chain reaction (PCR), CLO test, culture, and histological examination. Genomic DNA was amplified by PCR using the primer specific for the 109-bp product of 16S rRNA gene of H. pylori. The prevalence of cagA gene was examined in 37 persons who were positive in PCR for 16S rRNA gene of H. pylori. The PCR product using primer set specific for cagA gene was a 350-bp sized and represented mid-region of cagA gene. Resnlts: Thirty-two (68.1%) out of 47 persons were infected by H. pylori. Thirty-seven (78.7%) persons showed positive PCR result for H. pylori. The cagA was identified in 28 (75.7%) among 37 H. pylori positive persons.
CONCLUSIONS
The high prevalence of cagA gene in H, pylori-infeced gastric mucosa was observed in the persons with no specific gross abnormality in gastroscapic examination. These results indicate that the expression of cagA gene is common in H. pylori infected gastric mucosa in Korea. To canfirm the cytotoxie activity, the further studies using other primers are needed.