[S gene mutations in HBsAg/HBsAb double positive chronic hepatitis B patients].
OBJECTIVE
To investigate S gene mutations in HBsAg/HBsAb double positive chronic hepatitis B patients.


METHODS
HBV S gene from 8 patients (Group A) with HBsAg (+)/HBsAb (+) and 9 patients (Group B) with HBsAg (+)/HBsAb (-)was amplified by polymerase chain reaction (PCR) and sequencing. Both the distribution of genotype and serotype and the rate of MHR region were compared by Fisher's exact test. The mutation rate of both the DNA level and amino acid level was compared by t test.


RESULTS
No significant difference in distribution of genotypes was found between the two groups (P=0.153). In group A, 2 were genotype B, 6 were genotype C; In group B, 6 were genotype B, 3 were genotype C. No significant difference in distribution of serotypes was found between the two groups, either (P=0.218). In group A, 2 were adw, 5 were adr, 1 was ayr; In group B, 6 were adw, 3 were adr. The mutation rate of Pre-S1 region at both the DNA level (2.29% vs 1.80%, t=2.66, P more than 0.05) and the amino acid level (2.66% vs 1.59%, t=1.39, P>0.05) was not significantly different between these two groups; the mutation rate of Pre-S2 region in group A patients was significantly higher than that in group B at the DNA level (1.74% vs 0.91%, t=4.68, P<0.01), but not higher at the amino acid level (3.18% vs 2.05%, t=1.85, P>0.05), the mutation rate of S region in group A patients was significantly higher than that in group B at both the DNA level (2.13% vs 0.81%, t=6.00, P<0.01) and the amino acid level (4.37% vs 1.52%, t=5.32, P<0.01). Amino acid substitutions were found both within and beyond the MHR region. The rate of "a" determinant mutations in these two groups was also found to be significantly different (P<0.05).


CONCLUSIONS
Higher HBV S gene mutation rate exists in HBsAg/HBsAb double positive patients than that in HBsAg (+)/HBsAb (-) patients.
Zhang
Zhen-hua
ZH
Department of Infectious Diseases, the First Affiliated Hospital, Anhui Medical University, Hefei 230022, China.
Peng
Jing
J
Xia
Jian-bo
JB
Tian
Yong-jun
YJ
Jiang
Min
M
Yang
Dong-liang
DL
D000328:Adult; D000368:Aged; D001483:Base Sequence; D004279:DNA, Viral / Q000097:blood / Q000235:genetics; D005260:Female; D005814:Genes, Viral; D014644:Genetic Variation; D005838:Genotype; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000097:blood* / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000276:immunology / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D055815:Young Adult
D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens