Coinfection

HIV+ People Who Acquire Hepatitis C May Have Impaired HCV-specific Interferon Response

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People who already have HIV when they become infected with hepatitis C virus (HCV) appear to have reduced production of cytokines including natural interferons active against HCV, according to a study described in the November 15, 2012, Journal of Infectious Diseases.

Research has shown that HIV/HCV coinfected people tend to experience faster liver disease progression and respond less well to interferon-based therapy. Treatment with pegylated interferon aims to mimic the effect of naturally produced interferons in stimulating immune responses against HCV. Some studies find that people who are infected with HIV before HCV (typically the opposite is the case) may have especially rapid hepatitis C progression.

Jacqueline Flynn and Rosemary Ffrench from the Burnet Institute in Melbourne and fellow investigators with the Australian Trial in Acute Hepatitis C (ATAHC) looked at the effect of HIV infection on natural interferon production and activity in people newly infected with HCV.

In a laboratory study, the researchers directly compared HCV-specific T-cell responses and cytokine profiles of 40 ATAHC participants with acute hepatitis C, 20 of them HIV/HCV coinfected and 20 of them HIV negative.

Results

  • HIV infection had a detrimental effect on HCV-specific cytokine production in people with acute hepatitis C.
  • The effect was particularly notable for HCV-specific interferon gamma production.
  • Interferon gamma responses were both significantly lower in magnitude and smaller in breadth in HIV/HCV coinfected people.
  • Reduced interferon production was associated with lower peripheral CD4 T-cell counts, but not with detectable HIV viral load.

These findings suggest that HIV infection appears to impair natural interferon responses as well as response to interferon-based treatment. Fortunately, the new direct-acting hepatitis C drugs -- such as the HCV protease inhibitors boceprevir (Victrelis) and telaprevir (Incivek) -- can help overcome poor interferon response, and in the future most patients will likely be treated with interferon-free regimens.

10/26/12

Reference

JK Flynn, GJ Dore, G Matthews, R Ffrench, et al (ATAHC Study Group). Impaired Hepatitis C Virus (HCV)-Specific Interferon-Responses in Individuals with HIV Who Acquire HCV Infection: Correlation With CD4+ T-Cell Counts. Journal of Infectious Diseases 206(10):1568-1576. November 15, 2012.