New assays for quantitative determination of viral markers in management of chronic hepatitis B virus infection

Abstract

We performed a quantitative study of serum hepatitis B virus (HBV) markers, including new parameters such as pre-S1 antigen (Ag), pre-S2 Ag, and anti-HBx, in 88 chronic hepatitis B surface antigen (HBsAg) carriers. New IMx assays for HBsAg and immunoglobulin M (IgM) anti-HBc detection were also used. The population studied was composed of 65 chronic hepatitis cases (40 positive for hepatitis B antigen [HBeAg] and 25 positive for anti-HBe) and 23 anti-HBe-positive, asymptomatic HBsAg carriers. Serum HBsAg levels detected by IMx were higher in HBeAg-positive than in anti-HBe-positive HBsAg carriers (all patient subgroups included) and correlated with the serum HBV DNA level (P = 0.0001). Both pre-S1 and pre-S2 Ags were detected by enzyme immunoassays in almost all HBsAg carriers. Both pre-S1 and pre-S2 Ag titers correlated positively with the serum HBsAg concentration (P = 0.0001), but only the pre-S1 Ag titer correlated with the level of serum HBV DNA (P = 0.02). The detection of low levels of IgM anti-hepatitis B core (anti-HBc) antibodies by IMx was associated with the presence of liver disease (P = 0.05) but not with the level of viral replication. The prevalence of anti-HBx antibodies detected by the enzyme immunoassay was slightly, although not significantly, higher in patients with high levels of HBV DNA (greater than 100 pg/ml) than in patients without detectable HBV DNA (P = 0.16). In anti-HBe-positive chronic HBsAg carriers, the quantitative detection of serum HBV DNA, pre-S Ag titers, and IgM anti HBc allowed us to predict which patients suffered from chronic liver disease and/or supported viral replication (P < 0.05). In a follow-up study of eight patients undergoing antiviral therapy, the clearance of both pre-S1 Ag and HBV DNA was associated with a subsequent clearance of HBV. Therefore, the quantitative determination of HBV DNA, pre-S Ags, IgM anti-HBc may prove useful for the decision to use and the monitoring of antiviral therapy, especially in anti-HBe-positive HBsAg carriers.