Analysis of the entire nucleotide sequence of hepatitis B virus: characteristics of HBeAg-positive asymptomatic carriers, HBeAb positive asymptomatic carriers and patients with liver cirrhosis

Abstract

Entire nucleotide sequences of the HBV genome typical for various stages of HBV carriers are currently unknown. Comparison between conserved sequences in HBeAg-positive asymptomatic carriers (HBeAg ASCs) and mutations characteristic for HBeAb-positive asymptomatic carriers (HBeAb ASCs) are of clinical importance. In this study, we determined the entire nucleotide sequences of the HBV genome of patients infected with genotype C (HBeAg ASCs, 11 cases; HBeAb ASCs, seven cases; patients with liver cirrhosis (LC), five cases). Mutations in the entire nucleotide sequences were found more frequently in HBeAb ASCs than in HBeAg ASCs. In the precore/core (preC/C) region, amino acid mutations were more frequent in HBeAb ASCs (3.03%) than in HBeAg ASCs (0.00%) and patients with LC (0.69%). It was suggested that the mutations in the preC/C region had a close relationship with clinical status of HBV carriers. Mutations of leucine to isoleucine at a.a. 100 of the core region and of threonine to serine at a.a. 340 of the polymerase region were found frequently in HBeAb ASCs. In patients with LC, it was suggested that defective interfering particles (DI particles) play a role in the progression of stages. We conclude that attention should be given to mutations at a.a. 340 of the polymerase protein in addition to core protein.