Analysis of the hepatitis B virus precore and ORF-X sequences in patients with antibody to hepatitis B e antigen with and without normal ALT levels.

Serum samples from 20 anti-hepatitis B e antigen-positive patients with and without normal alanine aminotransferase (ALT) levels who had serum hepatitis B virus (HBV) DNA detectable only by polymerase chain reaction (PCR) were examined. Viral DNA was amplified by PCR, using primers that encompassed precore and ORF-X regions and sequenced directly, to investigate whether mutations in the nucleotide sequences of X and precore gene regions of HBV-DNA might be responsible for the difference in the activity of disease and in the levels of viral replication. The HBV-DNA concentration in patients with abnormal ALT levels was higher than in those with normal ALT. The amount of HBV-DNA correlated with the ALT levels (P < 0.05). Seventy-two percent of patients had HBV-DNA harboring the 1896 precore stop mutation, and there was a negative correlation between the percentage of precore mutant genotype and the HBV-DNA concentration (P < 0.05). Thirty percent of patients had mutations in ORF-X. Patients with ORF-X mutations had lower levels of HBV-DNA than those who had wild-type virus. The presence of mutations in precore and X regions may be related to a low HBV-DNA concentration and reduced biochemical activity in patients with anti-HBe.