Molecular
Virology and Hepatology Research, Faculty of Medicine,
Health Science Centre, Memorial University,
St. John's, Newfoundland, Canada A1B 3V6. timich@mun.ca
It is presumed that resolution of hepatitis C,
as evidenced by normalization of liver function
tests and disappearance of hepatitis C virus (HCV)
RNA from serum, as determined by conventional
laboratory assays, reflects virus eradication.
In this study, we examined the _expression of
the HCV genome in the sera, peripheral blood mononuclear
cells (PBMC), and, on some occasions, monocyte-derived
dendritic cells (DC) long
after resolution of hepatitis C by using
a highly sensitive reverse transcription (RT)-PCR-nucleic
acid hybridization (RT-PCR-NAH) assay.
The samples obtained from 16 randomly selected
patients (5 with spontaneous and 11 with treatment-induced
resolution), monitored for up to 5 years, were
studied by qualitative and semiquantitative RT-PCR-NAH
and by real-time RT-PCR to detect the HCV RNA
positive strand. The replicative HCV RNA negative
strand was examined in PBMC after culture with
a T-cell proliferation stimulating mitogen.
The findings show that HCV RNA was carried in
the convalescent-phase sera and/or PBMC in all
16 individuals investigated.
Also, DC from six
of seven patients were reactive for the HCV genome.
Importantly, traces of the HCV RNA negative strand,
suggesting progressing virus replication, were
detected in the majority of mitogen-stimulated
PBMC, including four samples collected 5 years
after recovery. Sequencing of the HCV 5' untranslated
region fragment revealed genotype 1b in four of
nine individuals examined and genotypes 1a and
2a in three and two patients, respectively.
These results imply that HCV RNA can
persist at very low levels in the serum and peripheral
lymphoid cells and that an intermediate replicative
form of the HCV genome can persist in PBMC for
many years after apparently complete spontaneous
or antiviral therapy-induced resolution of chronic
hepatitis C.