Antiviral Therapy May Promote Hepatitis B Virus Genotype Changes
 | Hepatitis
B Virus |
Hepatitis
B virus (HBV) is
known for its ability to mutate rapidly as it replicates, which enables it to
develop resistance to antiviral treatment.
As reported in the November
2008 Journal of Hepatology, a team of Spanish researchers assessed the
frequency of mixed HBV genotypes in people with chronic hepatitis B, as well as
genotype changes during natural disease evolution and as a result of antiviral
therapy.
In a cross-sectional study, the investigators analyzed serum samples
from 103 chronic hepatitis B patients. They also performed a longitudinal study
of HBV genotypes in 22 patients, 17 of whom were receiving antiviral therapy with
lamivudine (Epivir-HBV) and/or adefovir
(Hepsera). HBV genotyping was done using the INNO-LiPA HBV assay.
Results
•
HBV genotypes observed in the cross-sectional study were as follows:
•
A: 32% of cases;
•
D: 42%;
•
C: 2%;
•
F: 2%;
•
G: 7%, always combined with other genotypes.
•
mixed genotypes: 22% (mainly A/D, followed by A/G).
•
In the longitudinal study, genotype changes were observed in 9 patients, all of
whom were on treatment.
•
Genotype A strains were positively selected in 6 of these individuals, mainly
as mixed A/D.
•
In 6 patients, genotype A selection coincided with a decrease in HBV DNA levels.
Based
on these findings, the study authors concluded, "A high frequency of mixed
HBV genotypes was observed in our setting."
"Selection of genotype
A strains during treatment is likely an indication that sensitivity to therapy
differs between genotypes A and D," they continued. "The absence of
changes in untreated patients suggests that HBV genotype is stable without external
factors."
Hospital General Universitario Vall d'Hebrón,
Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades
Hepáticas y Digestivas (CIBERehd), Spain.
10/24/08
Reference
R
Jardi, F Rodriguez-Frias, M Schaper, and others. Analysis of hepatitis B genotype
changes in chronic hepatitis B infection: Influence of antiviral therapy. Journal
of Hepatology 49(5): 695-701. November 2008. (Abstract).
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