occult hepatitis B virus

2002落叶

Hepatology. 2007 Jan 26;45(2):277-285 [Epub ahead of print]

Molecular and functional analysis of occult hepatitis B virus isolates from
patients with hepatocellular carcinoma.

Pollicino T, Raffa G, Costantino L, Lisa A, Campello C, Squadrito G, Levrero
M, Raimondo G.

Unit of Clinical and Molecular Hepatology, Department of Internal Medicine,
University of Messina, Messina, Italy.

Occult HBV infection is characterized by the persistence of HBV DNA in the
liver of individuals negative for HBV surface antigen (HBsAg). Occult HBV
may exist in the hepatocytes as a free genome, although the factors
responsible for the very low viral replication and gene expression usually
observed in this peculiar kind of infection are mostly unknown. Aims of this
study were to investigate whether the viral genomic variability might
account for the HBsAg negativity and the inhibition of the viral replication
in occult HBV carriers, and to verify in vitro the replication capability of
occult HBV strains. We studied liver viral isolates from 17 HBV patients, 13
with occult infection and 4 HBsAg-positive. Full-length HBV genomes from
each case were amplified and directly sequenced. Additionally, full-length
HBV DNA from eight occult-HBV and two HBsAg-positive cases were cloned and
sequenced. Finally, three entire, linear HBV genomes from occult cases were
transiently transfected in HuH7 cells. Direct sequencing showed the absence
of mutations capable of interfering with viral replication and gene
expression in the major viral population of each case. Cloning experiments
showed highly divergent HBV strains both in HBsAg-positive and
HBsAg-negative individual cases (range of divergence 1.4%-7.1%). All of the
3 transfected full-length HBV isolates showed normal patterns of replication
in vitro. Conclusion: Multiple viral variants accumulate in the liver of
occult HBV-infected patients. Occult HBV strains are replication-competent
in vitro, suggesting that host, rather than viral factors are responsible
for cryptic HBV infection. (HEPATOLOGY 2007;45:277-285.).

结论：隐匿性肝炎的原因主要是宿主而不是病毒变种