SEQUENCING ANALYSIS OF THE TERMINAL PROTEIN REGION IN PATIENTS SHOWING PERSISTENT REMISSION OF CHRONIC HEPATITIS-B

Genomic variations in the polymerase gene of hepatitis B virus have no t been fully elucidated in the course of chronic hepatitis B virus inf ection. We investigated the terminal protein region, the amino-termina l domain of the polymerase gene, in chronic hepatitis B patients showi ng persistent biochemical and virological remission of the disease. Si x chronic hepatitis B patients followed for 3.5-9.1 years were examine d. Sequencing analysis of the terminal protein region was carried out on sera from the beginning and the end of follow-up in each patient. A mino acid substitution was observed in the terminal protein region in five of the six patients during follow-up. Three novel amino acid subs titutions were found in two patients: (a) tryptophan to cysteine at co don 52 in one patient, (b) threonine to alanine at codon 60; and (c) p roline to histidine at codon 72 in another patient. Two ((a) and (b)) of the three novel amino acid substitutions caused a change in the pre dicted secondary structure of the protein. In conclusion, novel amino acid substitutions were identified in the terminal protein region duri ng the course of the remission of the chronic hepatitis B virus infect ion, (C) 1997 Elsevier Science Ireland Ltd.