Molecular and genetic properties of hepatitis b virus and their clinical role in chronic hepatitis B

Abstract

Objective. To study the molecular and genetic properties of hepatitis B virus (HBV) and their relationship with clinical and laboratory parameters in patients with chronic HBV infection.Materials and methods. The study group included 228 patients with chronic HBV-infection. Routine hematological and biochemical tests, serum HBV DNA level, liver fibrosis (F) stage were measured. The determination of HBV genotype, subtype and drug resistance mutations was carried out by sequencing followed by phylogenetic analysis in 131 patients.Results. HBV DNA level above 2000 IU/ml was found in 68,4% of patients. The majority of the patients were HBeAg-negative (87,3%), they had viral load lower as compared with those HBeAg-positive (p<0,001). The viral load had a positive correlation with aminotransferases activity and severity of liver fibrosis, and negative correlation with the platelets count, albumin and prothrombin levels. HBV DNA level in patients with advanced liver fibrosis (F2-F4) was significantly higher vs. those with liver fibrosis stage F0-F1 (p=0,001). In patients with viral load above 2000 IU/ml hepatic necrosis, hypoalbuminemia and dysproteinemia were more pronounced. Phylogenetic analysis revealed the circulation of HBV genotypes D (74,8%) and A (23,7%), as well as genotype C and recombinant form D/A/D were detected. Patients with genotype D had higher aminotransferases and gammaglutamiltransferase (p<0,05) levels, and higher proportion of advanced liver fibrosis (F2-F4, p=0,04) vs. those with genotype A; no differences in viral load were found. Antiviral treatment is indicated in 59,2% of patients with genotype D, and only in 38,7% with genotype A (p=0,046).