Sequence analysis of the S gene region in HBV DNA from patients positive for both HBsAg and HBsAb tests.

Abstract

AIMS:

  To study the characteristics of mutation in the amino acids coded by the S gene region in the HBV DNA sequence and to comprehensively explore and analyze the cause of the double positive result phenomena in both HBsAg and HBsAb tests.

METHODS:

  Specimens collected from 43 cases of chronic hepatitis B patients with positive results for both HBsAg and HBsAb tests were used as the experimental group; specimens collected from 43 cases randomly picked from all patients with chronic hepatitis B with a single positive result for HBsAg test were used as the control group. In HBV DNA, the S gene region was amplified and sequenced. Amino acid sequences were grouped, and mutations were analyzed based on the sequencing results.

RESULTS:

  The patients were infected with HBV of the genotype B and C and those who with genotype C show more mutations than genotype B carriers. Compared with the control group, the experimental group had a marked increase in S gene amino acid mutations; a higher amino acid mutation rate was observed in the first loop (aa124-137) of the a-determinant (aa124-147) and there was a statistical difference (genotype B: 2.68% vs. 0.00%, P = 0.041; genotype C: 7.14% vs. 2.01%, P < 0.001).

CONCLUSION:

  The first loop in a-determinant of S gene sequence possesses a large numbers of mutated amino acids, leading to changes of antigenicity and simultaneous positive results in both HBsAg and HBsAb tests finally.

• Authors: Lei Wang, Hua Liu, Xiaoxiao Ning, Feng Gao
• Journal: Hepatology research : the official journal of the Japan Society of Hepatology (Hepatol Res) Vol. 40 Issue 12 Pg. 1212-8 (Dec 2010) ISSN: 1872-034X [Electronic] Netherlands
• PMID: 20973882 (Publication Type: Journal Article)
• Copyright: © 2010 The Japan Society of Hepatology.