Characteristics of hepatitis B X antigen, antibodies to X antigen, and antibodies to the viral polymerase during hepatitis B virus infection.

The characteristics of hepatitis B virus (HBV) X antigen (HBxAg) and antibodies against the X antigen (anti-HBx) and the viral polymerase (anti-pol) were determined in 85 HBV-infected patients. HBxAg was detected in sera positive for HBV e antigen (HBeAg) and HBV DNA in patients with acute and chronic hepatitis, while anti-HBx appeared when markers of viral replication became undetectable. HBxAg was common in the liver among patients with chronic hepatitis independent of HBV replication markers but was closely correlated with elevated alanine aminotransferase, implying that HBxAg in liver may be important in the pathogenesis of chronic infection. Anti-pol was detected in many samples positive for HBeAg and HBV DNA and less often in serum samples without markers of HBV replication, suggesting that this marker could reflect ongoing viral replication in the liver, even though such markers were absent from sera.