Abstract and Introduction
It is estimated that 4–5 million HIV-infected patients are coinfected with HCV. The impact of HIV on the natural course of HCV infection is deleterious. This includes a higher rate of HCV persistence and a faster rate of fibrosis progression. Coinfected patients show poor treatment outcome following standard HCV therapy. Although direct antiviral agents offer new therapeutic options, their use is hindered by potential drug interactions and toxicity in HIV-infected patients under HAART. Overtime, a large reservoir of HCV genotype 1 patients will accumulate in resource poor countries where the hepatitis C treatment is not easily affordable and HIV therapy remains the primary health issue for coinfected individuals. HCV vaccines represent a promising strategy as an adjunct or alternative to current HCV therapy. Here, the authors review the pathogenesis of hepatitis C in HIV-infected patients, with a focus on the impact of HIV on HCV-specific immune responses and discuss the challenges for vaccine development in HIV–HCV coinfection.
HIV-1 and HCV may cause persistent infections with long-term high-level viremia in spite of a specific immune response. Both infections progress silently over several years, leading to the destruction of the immune system in the case of HIV-1 and liver cirrhosis in the case of HCV. Unlike HIV infection, HCV is spontaneously cleared in 25% of cases and curable in more than 50% of patients when treated with interferon (IFN)-based combination therapies.[2,3] Coinfection is frequent because of the shared risk factors for viral transmission, as HCV and HIV are both transmitted through exposure to blood and sexual exposure, although with different efficiencies. Recent epidemiologic and clinical studies showed that the introduction of HAART has improved the survival of HIV-infected patients, while HCV-associated liver diseases have become a leading cause of death in the coinfected population. The standard treatment for HCV infection in HIV–HCV-coinfected patients is similar to that of HCV-monoinfected patients, although significant toxicity is associated with pegylated IFN-α and ribavirin in coinfected patients. Therefore, the development of new therapeutic and preventive strategies against HCV in HIV-infected individuals has become a priority. This review summarizes the current knowledge on the pathogenesis of hepatitis C in HIV-infected patients, with a focus on the impact of HIV on HCV-specific immune responses and discusses the challenges for HCV vaccine development in HIV–HCV coinfection.
Expert Rev Vaccines. 2012;11(7):791-804. © 2012 Expert Reviews Ltd.