Emergence of an S gene mutant during thymosin alpha1 therapy in a patient with chronic hepatitis B.
The presence of a hepatitis B virus S gene mutant was investigated in a patient being treated with thymosin alpha1. He was seropositive for hepatitis B e antigen throughout therapy but was intermittently seronegative for hepatitis B surface antigen (HBsAg) by an RIA. Sequence analysis revealed an S gene mutant in HBsAg-seronegative serum with two consecutive amino acid substitutions: threonine115-to-isoleucine and threonine116-to-asparagine, whereas no amino acid substitution or deletion was found in the pre-S region. A site-directed mutagenesis experiment confirmed that these mutations were responsible for the failure to detect HBsAg. In summary, an S gene mutant was identified in an HBsAg-seronegative patient. The mutations were located outside the putative "a" determinant. The emergence of an S gene mutant during thymosin alpha1 treatment suggests that enhanced host immunity against HBsAg may play a role in its antiviral activity.
Tang
J H
JH
Department of Pathology, Chang Gung Memorial Hospital and University, Taipei, Taiwan.
Yeh
C T
CT
Chen
T C
TC
Hsieh
S Y
SY
Chu
C M
CM
Liaw
Y F
YF
D000328:Adult; D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000627:therapeutic use*; D005814:Genes, Viral; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000097:blood / Q000188:drug therapy / Q000276:immunology / Q000821:virology*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000627:therapeutic use
D000998:Antiviral Agents; D006514:Hepatitis B Surface Antigens; D013947:Thymosin; D000077596:Thymalfasin