Detection of Core Gene Deletion and Its Clinical Significance in Chronic Hepatitis B Virus infection

Kang, So Young; Kim, Young Sik; Lee, Kwang Gil; Lee, Hee Joo; Lee, Woo In; Cha, Sung Ho; Suh, Jin Tae

Abstract

BACKGROUND
In the course of chronic hepatitis B virus (HBV) infections, a point mutation or core gene deletion has been attributed to play a role in persistence of HBV infection. This study was undertaken to determine the prevalence of core gene deletion in chronic HBV infections, molecular characteristics, and its clinical significance. METHODS: Among 276 patients with positive results in HBV PCR for precore and core region, patients with smaller bands in addition to the band of expected wild type size, suggestive of deletion, were analyzed by direct sequencing, and hospital records were reviewed on 217 patients. RESULTS: The prevalence of core gene deletion among patients with positivity in HBV PCR was 12.7% (35/276) and they always existed together with wild type. Seventeen patients were further studied by direct sequencing and 16 patients had similar positions of deletion in the center of core gene (nt 2000-2200). Of 35 patients with core gene deletion, 26 (74.3%) were HBeAg-positive and 7 (20.0%) were anti-HBe-positive. There were no significant differences in AST, ALT and HBV DNA quantitation between the wild type and the deletion groups. CONCLUSIONS: HBV core gene deletion is frequently found in chronic HBV infections and has some common features in deleted position, serologic markers and clinical state. However, the mechanism and time at which deletion mutants appear and disappear, and their clinical significances are not fully understood. By longitudinal studies for chronic hepatitis B patients, we should be able to demonstrate the immunologic significance of the core gene deletion mutation.