Biochemical markers of hepatitis B virus in disease

Abstract

Hepatitis B virus (HBV) DNA, its different forms and HBV DNA polymerase (DNAp) give much information on the status of HBV infection. The molecular hybridization assay for HBV DNA is the most sensitive and useful of these markers. With the application of the polymerase chain reaction its sensitivity can be increased further by a factor of about 10 5 . Patients with acute HBV infection show a transient rise in serum HBV DNA and DNAp. Persistence of these two markers is predictive of the HBsAg carrier state. In asymptomatic carriers serum HBV DNA is generally found together with HBeAg, but this concordance breaks down with increasingly severe liver disease: chronic persistent hepatitis, chronic active hepatitis and hepatocellular carcinoma (HCC). A second type of discordance appears in these conditions, the appearance in serum HBV DNA together with anti-HBe. There are 7 distinct HBV DNA forms. Serum and liver HBV DNA specimens usually consist of a mixture of replicative forms. However, the supercoil may persist in liver when other replicative forms have been suppressed by interferon. The integration of HBV DNA into human liver DNA can take place in at an early stage in the progression from HBV infection to HCC; the duration of infection may increase the chances of integration. Neither the sites of integration, the HBV DNA inserts, nor their flanking sequences reveal a consistent pattern. On balance, neither free nor integrated HBV DNA in liver seems to be necessary for maintenance of the tumourous condition.