Nucleotide sequence analysis of precore and proximal core regions in patients with chronic hepatitis B treated with interferon.
The aim of the study was to estimate the prevalence of HBeAg defective mutants among patients with chronic hepatitis B (CHB) in the United States and to study the effect of interferon-alpha (IFN-alpha) on determining the occurrence of mutations in the HBV precore and proximal core regions. Twenty CHB patients who were treated with IFN-alpha were studied. Initially, all were HBV DNA positive by dot-blot hybridization; 17/20 were HBeAg positive, and 3/20 were anti-HBe positive. The precore (87 nt) and proximal core (81 nt) regions were sequenced after PCR amplification by the dideoxy chain termination method. In pretreatment sera, 15/20 patients harbored wild-type HBV only, while in 5/20 at least one nucleotide substitution was found. Mutations that prevent HBeAg synthesis were found in three patients, all of whom had G-to-A substitution at nt 1896 and two of them were anti-HBe positive. Follow-up sera were available in 18 patients. With respect to pretreatment specimen, 15/18 patients had no changes in the sequenced regions after therapy. Sequence changes were observed in the remaining three patients: In one an HBeAg defective strain was replaced by a wild-type strain; in the second a wild-type strain was replaced by an HBeAg defective strain; and in the third two mutations changing the deduced amino acid sequence of the core protein developed in the wild-type strain. In conclusion, most of our patients (85%) were initially infected by HBV strains having no mutations that prevented HBeAg synthesis. IFN-alpha therapy infrequently resulted in the appearance of mutations in the precore and proximal core regions.
Laskus
T
T
Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Rakela
J
J
Persing
D H
DH
D000328:Adult; D000368:Aged; D001483:Base Sequence; D002908:Chronic Disease; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000382:microbiology / Q000628:therapy*; D006513:Hepatitis B e Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics; D006801:Humans; D016898:Interferon-alpha / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction
D004279:DNA, Viral; D006513:Hepatitis B e Antigens; D016898:Interferon-alpha