Use of quantitative assays for hepatitis B e antigen and IgM antibody to hepatitis B core antigen to monitor therapy in chronic hepatitis B

Objectives: We evaluated the clinical utility of IgM antibody to the hepatitis B (HB) core antigen (anti-HBc) and HB e antigen (HBeAg) serum levels in patients with chronic HB receiving interferon alfa. Methods: Stored serum from 47 patients with chronic HB participating in a controlled trial of interferon alfa therapy (10 million U three times a week for 16 wk) were analyzed. All were seropositive for HB surface Ag, HBeAg, and HB virus (HBV) DNA before entry. IgM anti-HBc index values and HBeAg standard values were determined by automated microparticle enzyme immunoassay on samples drawn just before therapy and 6 months later. Ten normal subjects were tested as controls. IgM anti-HBc and HBeAg levels were compared to initial serum HBV DNA, DNA polymerase, serum aminotransferase levels, and demographic features. Serial IgM anti-HBc levels were also obtained during and after therapy in 10 responders and five nonresponders, and serial HBeAg levels were also obtained during and after therapy in four responders and four nonresponders. Results: Neither IgM anti-HBc nor HBeAg levels correlated significantly with values for serum HBV DNA, DNA polymerase, aminotransferases, or demographic features. The initial mean IgM anti-HBc level among the 15 responders to therapy (loss of HBeAg and HBV DNA from serum) was no different from that in nonresponders (mean 1.15 vs 1.27, p = not significant). However, the initial mean HBeAg level was significantly lower in responders than in nonresponders (749.4 vs 1356.4,p = 0.019). Among 10 responders, IgM anti-HBc levels decreased progressively over time, so that at latest follow-up (1.5-4 yr later, mean 2.6 yr), the mean had decreased from 1.325 to 0.312 (p = < 0.001). Among five nonresponders, the mean did not change significantly over 1.5-3 yr (mean 2.2 yr) (1.26 vs 1.08, p = not significant). HBeAg values fell in parallel with HBV DNA and DNA polymerase values in four responders tested but remained elevated in four nonresponders. Conclusions: HBeAg levels, but not IgM anti-HBc levels, are useful in predicting response to interferon alfa, with responders tending to have lower pretreatment HBeAg levels than nonresponders. HBeAg levels may be used to monitor response to interferon alfa in patients with chronic HB.