Analyses of the association between antibody titre and pathogenicity before and after eradication: results of the Kyushu and Okinawa population study, a retrospective observational cohort study.

OBJECTIVES

To assess the utility of antibody testing, we evaluated the correlation between the antibody titre and -associated pathogenicity and the changes in antibody titre after eradication therapy.

DESIGN

A retrospective observational cohort study.

SETTING AND PARTICIPANTS

From 2004 to 2016, medical check-ups were performed in different regions of Japan. In total, 324 subjects infected with who received eradication therapy were enrolled; was eradicated in 266 of these subjects. We examined the associations between antibody titre with pepsinogen and the presence or absence of -associated pathogenic proteins, such as cytotoxin-associated gene A and vacuolating cytotoxin gene A, at baseline and after eradication therapy.

RESULTS

The antibody titre showed a positive correlation with pepsinogen II and a negative correlation with the pepsinogen I/II ratio. Moreover, the antibody titre significantly correlated with the positive rates of -associated pathogenic protein before eradication therapy. Antibody titres decreased after eradication, the pepsinogen I/II ratio increased and the -associated pathogenic protein-positive rate decreased in patients with successful eradication. The determination of eradication using the decline in antibody titre 6 months after eradication therapy was useful (area under the receiver operating characteristic curve: 0.98).

CONCLUSIONS

Our data indicate that the antibody titre may represent the degree of pathogenicity. The antibody titre was associated with attenuation of pathogenicity in patients with eradication, indicating the clinical utility of antibody testing.