USE OF QUANTITATIVE ASSAYS FOR HEPATITIS-B E-ANTIGEN AND IGM ANTIBODYTO HEPATITIS-B CORE ANTIGEN TO MONITOR THERAPY IN CHRONIC HEPATITIS-B

Objectives: We evaluated the clinical utility of IgM antibody to the h epatitis 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 con trolled trial of interferon alfa therapy (10 million U three times a w eek 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 l ater. Ten normal subjects were tested as controls. IgM anti-HBc and HB eAg levels were compared to initial serum HBV DNA, DNA polymerase, ser um aminotransferase levels, and demographic features. Serial IgM anti- HBc levels were also obtained during and after therapy in 10 responder s and five nonresponders, and serial HBeAg levels were also obtained d uring and after therapy in four responders and four nonresponders. Res ults: Neither IgM anti-HBc nor HBeAg levels correlated significantly w ith values for serum HBV DNA, DNA polymerase, aminotransferases, or de mographic features. The initial mean IgM anti-HBc level among the 15 r esponders to therapy (loss of HBeAg and HBV DNA from serum) was no dif ferent from that in nonresponders (mean 1.15 vs 1.27, p = not signific ant). However, the initial mean HBeAg level was significantly lower in responders than in nonresponders (749.4 vs 1356.4,p = 0.019). Among 1 0 responders, IgM anti-HBc levels decreased progressively over time, s o 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 remain ed elevated in four nonresponders. Conclusions: HBeAg levels, but not IgM anti-HBc levels, are useful in predicting response to interferon a lfa, with responders tending to have lower pretreatment HBeAg levels t han nonresponders. HBeAg levels may be used to monitor response to int erferon alfa in patients with chronic HB.