Characterization of the basal core promoter and precore regions in anti-HBe-positive inactive carriers of hepatitis B virus

摘要

SummaryBackground The study of hepatitis B virus (HBV) genomic heterogeneity has become a major issue in investigations aimed at understanding the relationship between {HBV} mutants and the wide spectrum of clinical and pathological conditions associated with {HBV} infection. Although most chronically infected {HBV} patients are inactive carriers, several virological aspects of this state remain unclear. Methods In order to determine the prevalence and clinical significance of mutations in the basal core promoter (BCP) and precore (pC) regions among inactive carriers, the nucleotide sequences from 41 inactive carriers were analyzed and compared with those from 29 individuals with chronic active hepatitis. Results Genotypes A (24.3%), D (37.1%), {F1b} (12.9%), and {F4} (18.6%) were the most prevalent. Mutations in the BCP/pC regions were observed in most of the inactive carriers (92.7%) and in most of the patients with chronic active hepatitis (93.1%). The prevalence of mutation 1764A was significantly higher in patients with chronic active hepatitis (65.5%) than in inactive carriers (36.6%) (p?=?0.038), whereas the prevalences of mutations at the other positions analyzed were not significantly different. Older patients (>50 years) showed BCP/pC patterns with a higher number of substitutions. Mutations were found to be biased by genotype: the 1896A mutation was highly prevalent in genotypes D and F4, while alternative substitutions in the pC region were more prevalent in genotypes A and F1b. Conclusions Mutations in the BCP/pC regions are the hallmark of chronic anti-HBe-positive individuals; nevertheless, the even distribution of mutations in active and inactive carriers suggests that BCP/pC mutations may occur during {HBV} infection not strictly related to the {HBV} infection activity.