Hepatitis C Virus in the Brain May Impair Cognitive Function in HIV-HCV Coinfected People

Both HIV and hepatitis C virus (HCV) have been linked to neurocognitive impairment, and some studies suggest that coinfection with both viruses may increase the risk and/or severity.

However, few studies have assessed the penetration of HCV into the central nervous system (the brain and spinal cord) and its clinical and neuropathological impact in HIV-HCV coinfected individuals.

As reported in the in the August 1, 2007 Journal of Infectious Diseases, Scott Letendre from the University of California at San Diego and colleagues studied the distribution of HCV in the brains of HIV positive patients.

They studied post-mortem (autopsy) brain tissue samples from 12 HIV-HCV coinfected individuals and 13 subjects with HIV alone, using a nested polymerase chain reaction (PCR) assay to detect HCV RNA (an indicator of viral replication).

Results

• The presence of HCV RNA in the central nervous system was associated with:

- history of methamphetamine use;

- considerable antemortem (pre-death) cognitive impairment;

- abundant astrogliosis (an increased number of astrocytes -- a type of support cell in the brain -- which is typically associated with injury to neurons);

- less-severe HIV-related encephalitis (brain inflammation).

• HCV antigens were detected by immunoblot assay, using heparin-purified brain samples.

• HCV immunoreactivity was detected in astrocytes and in macrophage-microglial cells.

Conclusion

In conclusion, the authors wrote, "The results support the hypothesis that HCV traffics into the HIV-infected brain, where it might lead to a productive coinfection associated with cognitive impairment."

09/07/07

Reference
S Letendre, AD Paulino, E Rockenstein, and others. Pathogenesis of hepatitis C virus coinfection in the brains of patients infected with HIV. Journal of Infectious Diseases 196(3): 361-370. August 1, 2007.