Sequencing analysis of the terminal protein region in patients showing persistent remission of chronic hepatitis B

Abstract

Abstract Genomic variations in the polymerase gene of hepatitis B virus have not been fully elucidated in the course of chronic hepatitis B virus infection. We investigated the terminal protein region, the amino-terminal domain of the polymerase gene, in chronic hepatitis B patients showing persistent biochemical and virological remission of the disease. Six chronic hepatitis B patients followed for 3.5–9.1 years were examined. Sequencing analysis of the terminal protein region was carried out on sera from the beginning and the end of follow-up in each patient. Amino acid substitution was observed in the terminal protein region in five of the six patients during follow-up. Three novel amino acid substitutions were found in two patients: (a) tryptophan to cysteine at codon 52 in one patient: (b) threonine to alanine at codon 60: and (c) proline to histidine at codon 72 in another patient. Two ((a) and (b)) of the three novel amino acid substitutions caused a change in the predicted secondary structure of the protein. In conclusion, novel amino acid substitutions were identified in the terminal protein region during the course of the remission of the chronic hepatitis B virus infection.