Brief Reports
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 28, 2005; 11(24): 3751-3755
Published online Jun 28, 2005. doi: 10.3748/wjg.v11.i24.3751
Relation of CagA seropositivity to cagPAI phenotype and histological grade of gastritis in patients with Helicobacter pylori infection
Tadashi Shimoyama, Shinsaku Fukuda, Fumika Nakasato, Tetsuro Yoshimura, Tatsuya Mikami, Akihiro Munakata
Tadashi Shimoyama, Shinsaku Fukuda, Fumika Nakasato, Tetsuro Yoshimura, Tatsuya Mikami, Akihiro Munakata, First Department of Internal Medicine, Hirosaki University School of Medicine, Hirosaki, Japan
Author contributions: All authors contributed equally to the work.
Supported by the Grant-in-Aid from the Ministry of Education, Science and Culture (Cont. No. 15790333), Japan
Correspondence to: Tadashi Shimoyama, First Department of Internal Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan. tsimo-hki@umin.ac.jp
Telephone: +81-172-39-5053 Fax: +81-172-37-5946
Received: November 29, 2004
Revised: November 30, 2004
Accepted: December 8, 2004
Published online: June 28, 2005
Abstract

AIM: Infection with Helicobacter pylori (H pylori) possessing the cag pathogenicity island (PAI) has been associated with severe clinical outcome and CagA-antibody has been used to indicate cagPAI-positive infection. The aim of this study was to examine the accuracy of CagA seropositivity to indicate the virulence of the cagPAI in Japan.

METHODS: Sixty isolates of H pylori cultured from gastric biopsies were examined by polymerase chain reaction assays for the presence of cagA, cagE and VirD4. Anti-CagA IgG antibody in matching sera was tested by both ELISA and immunoblot assay. Histological grade of gastritis was graded according to the updated Sydney System.

RESULTS: Amongst 53 patients infected with cagA+/cagE+/VirD4+ strain, 38 were CagA seropositive. There were four patients infected with strains possessing incomplete cagPAI. Two out of three patients with cagA+/cagE-/VirD4- infection were CagA seropositive, while a patient with cagA-/cagE+/VirD4+ infection was CagA seronegative. Accuracy of ELISA to predict bacterial possession of cagA was 61.7% whereas 58.3% for cagE and VirD4. The immunoblot assay showed relatively higher sensitivity and showed better accuracy. The lower grade of gastric mucosal inflammatory infiltration was seen in false CagA-seronegative patients.

CONCLUSION: Some serodiagnosis does not seem to have enough accuracy to indicate virulence of cagPAI, particularly in infection of strains with incomplete cagPAI. The degree of gastric mucosal inflammation may affect the results of CagA serodiagnosis.

Keywords: CagA seropositivity, cagPAI, Gastric inflammation