RESUMEN
Mutations in the core promoter and precore regions of HBV cause down-regulation of HBeAg. These mutations are associated with chronic hepatitis, cirrhosis and Hepato Cellular Carcinoma (HCC). This study was carried out to sequence analysis of HBV core gene in HBsAg- positive blood donors in Iran. A total of 50 HBsAg- positive blood donor samples were examined in this study. Serological markers of hepatitis B including: HBsAg, HBeAg, HBeAb and HBcAb were measured by ELISA method. HBV-DNA was extracted from the sera, and then PCR was performed on extracted HBV-DNA using specific primer of gene C. After direct sequencing, the nucleotide sequences from 50 blood donors were analyzed using a reference sequences and then phylogenetic analysis was performed. Also, the line probe assay was used to detect mutations. The majority of donors (62.5%) were in the age group of 29 - 40 years old. Among all the HBV DNA positive cases, 87.8% were HBeAg negative. The prevalence of PC and BCP mutants were 12% and 55% respectively, among asymptomatic HBV infected blood donors by direct sequencing method. The results of this study showed that some of HBV infected blood donors had mutation in core gene of HBV and amino acid changes in B cell, T helper and CTL epitopes that can cause reducing HBe and HBc antigenicity in asymptomatic HBV infected blood donors and the development of escape mutants from host immune.