A novel hepatitis B virus mutant coexisting with wild type virus in a carrier with negative HBsAg yet positive HBeAg and anti-HBs.
BACKGROUND
Occult infection of hepatitis B virus (HBV) has important impacts on both public health and clinical medicine.


OBJECTIVE
To characterize the sequences of HBV S region in a chronic carrier with occult HBV infection.


METHODS
Serological markers for HBV were tested by commercial kits. Western blotting was performed to detect HBsAg. PCR was used to amplify HBV S region; the resultant products were sequenced directly and cloned and then sequenced.


RESULTS
Tests with commercial kits showed that the carrier was HBsAg negative yet HBeAg positive. HBsAg was positive in Western blotting analysis. Although anti-HBs titers were as high as 5356-11,578mIU/ml, serum HBV DNA was positive, ranging from 370 to 491copies/ml. Wild type and mutant HBV coexisted in circulation. The mutant virus had mutations in both preS2 and S genes: the preS2 ATG mutated to ATA, and the S gene had a 15-nucleotide repeat insertion in the a determinant. By Blast search in the GenBank, the mutant virus had not been identified before. Nevertheless, the carrier had no signs of liver dysfunction during follow-up period.


CONCLUSIONS
We identified a novel mutant HBV coexisted with wild type virus in a carrier with negative HBsAg and positive HBeAg and high level of anti-HBs.
Zhou
Yi-Hua
YH
Department of Laboratory Medicine, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.
Zhou
Jianxin
J
Li
Lei
L
Bi
Yongchun
Y
Liu
Yong
Y
Pan
Jinshun
J
Wu
Chao
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D002353:Carrier State / Q000097:blood / Q000276:immunology* / Q000821:virology; D005500:Follow-Up Studies; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006513:Hepatitis B e Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000276:immunology* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data
D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens