Coinfected Have Stronger CD8 T-cell Response to HCV
people coinfected with hepatitis C virus (HCV) demonstrated
stronger CD8 T-cell responses against HCV, which may contribute
to accelerated liver disease progression.
estimated one-third of HIV positive
people also have HCV, which is
transmitted in similar ways. HIV/HCV
coinfected individuals experience more rapid liver
fibrosis progression on average, may be more likely to develop
and tend to respond less well to interferon-based
hepatitis C treatment.
study reported in the March
2011 Journal of Viral Hepatitis shed further light
on the biological mechanisms underlying different outcomes in
HIV/HCV coinfected and HCV monoinfected patients.
Barrett from Memorial University of Newfoundland and colleagues
evaluated the role of the immune system in accelerated liver
disease progression in coinfected people.
In general, liver disease develops over years in people with
HIV/HCV coinfection, compared to decades with HCV monoinfection,
the study authors noted as background. Fibrosis is not caused
directly by the virus, however, but rather is an outcome of
the immune response against it, which includes inflammation
and activation of cell-repair mechanisms.
Some investigators, including Daniel Fierer and colleagues at
Mt. Sinai Medical Center in New York City, have described very
rapid fibrosis progression in a cohort of men who were already
HIV positive when they subsequently acquired HCV, presumably
In the present analysis, the researchers compared the frequency,
magnitude, breadth, and specificity of peripheral blood CD4
and CD8 T-cell responses between HIV positive and HIV negative
hepatitis C patients. They also looked at differences between
coinfected people with various HCV antibody and HCV RNA viral
general, HIV/HCV coinfection tended to reduce the frequency
and breadth of anti-HCV CD8 T-cell responses.
CD8 T-cell responses that were present were substantially
stronger in coinfected compared with HCV monoinfected individuals.
all groups, HCV-specific CD4 T-cell responses were rare
and weak, regardless of either current or nadir (lowest-ever)
CD4 counts in HIV positive individuals.
coinfected people without anti-HCV antibodies demonstrated
restricted breadth of HCV-specific CD8 T-cell responses
and lower B-cell counts.
on these findings, the study authors concluded, "The greatest
difference between HIV/HCV coinfected and HCV monoinfected groups
was substantially stronger HCV-specific CD8+ T-cell responses
in the HIV[/HCV] coinfected group, which may relate to accelerated
liver disease in this setting."
affiliations: Immunology Program, Division of BioMedical Sciences,
Faculty of Medicine, Memorial University of Newfoundland, St.
John's, NL, Canada; Department of Internal Medicine, Dalhousie
University, Halifax, NS, Canada; HIV Program, Eastern Health
District, St. John's, NL, Canada; Hepatitis C Program, Division
of Gastroenterology, Capital Health District, Halifax, NS, Canada.
Barrett, M Gallant, C Howley, et al. Stronger hepatitis C virus-specific
CD8(+) T-cell responses in HIV coinfection. Journal of Viral
Hepatitis 18(3):170-180 (abstract).