Objectives: To clarify the association of hepatitis B virus mutants in basal core gene promoter and pre-c region with serum HBeAg state and persistent HBV infection.
Methods: 32 patients, who infected with hepatitis B virus and suffered from several exacerbation during the course of this disease, were followed up for an average of 20.8 months. Using two mis-matched primers to amplify BCP and pre-c gene fragments, in combination with restricted fragment length polymorphism assay, we studied the presence of these two mutants(nt 1762A-->T, 1764G-->A and nt1896G-->A) in 105 serum samples. Direct sequencing was performed on 15 patients' serial samples to identify the efficiency of these rapid and simple methods and other variations in these regions.
Results: The presence of these two kinds of mutants increased during the following-up, (62.5% > 46.9%; 31.3% > 12.5%). In most cases, two mutants prevailed and finally displaced the wild type virus; the serology of HBeAg was affected predominantly by the ratio of BCP mutant to wild type.
Conclusion: BCP and pre-c mutants emerged in the course of chronic infection and were selected positively by the inflammation activity. The serological conditions of HBeAg were changed when the predominant situations of these two mutants were established. The survival of these two mutants implied that mutations in these two regions may contribute to the persistent infection of hepatitis B virus.