Early after symptom onset, HCV-specific CD4+ T cell responses are primed and detectable in patients regardless of clinical outcome, but without early antiviral therapy these T cells become exhausted or deleted in chronically infected patients.

BackgroundHepatitis C virus (HCV)-specific T cell responses are critical for spontaneous resolution of HCV viremia. Here we examined the effect of a lymphotropic virus, HIV-1, on the ability of coinfected patients to maintain spontaneous control of HCV infection.Methods and FindingsWe measured T cell responsiveness by lymphoproliferation and interferon-γ ELISPOT in a large cohort of HCV-infected individuals with and without HIV infection. Among 47 HCV/HIV-1-coinfected individuals, spontaneous control of HCV was associated with more frequent HCV-specific lymphoproliferative (LP) responses (35%) compared to coinfected persons who exhibited chronic HCV viremia (7%, p = 0.016), but less frequent compared to HCV controllers who were not HIV infected (86%, p = 0.003). Preservation of HCV-specific LP responses in coinfected individuals was associated with a higher nadir CD4 count (r 2 = 0.45, p < 0.001) and the presence and magnitude of the HCV-specific CD8+ T cell interferon-γ response (p = 0.0014). During long-term follow-up, recurrence of HCV viremia occurred in six of 25 coinfected individuals with prior control of HCV, but in 0 of 16 HIV-1-negative HCV controllers (p = 0.03, log rank test). In these six individuals with recurrent HCV viremia, the magnitude of HCV viremia following recurrence inversely correlated with the CD4 count at time of breakthrough (r = −0.94, p = 0.017).ConclusionsThese results indicate that HIV infection impairs the immune response to HCV—including in persons who have cleared HCV infection—and that HIV-1-infected individuals with spontaneous control of HCV remain at significant risk for a second episode of HCV viremia. These findings highlight the need for repeat viral RNA testing of apparent controllers of HCV infection in the setting of HIV-1 coinfection and provide a possible explanation for the higher rate of HCV persistence observed in this population.

Improved screening of the blood supply and safer injection practice have led to a decreased prevalence of hepatitis C virus (HCV) worldwide over the past decade. However, those who are coinfected with HIV and HCV experience synergistic interaction between the viruses, leading to accelerated liver fibrosis and possibly increased HIV progression. Left untreated, these coinfected patients experience higher mortality compared with monoinfected individuals. The recent availability of highly efficacious direct-acting antivirals (DAAs) provides opportunity to prioritize coinfected patients for curing HCV, which can improve liver-related and overall mortality. This review summarizes the epidemiology, virology, and natural history of coinfection. Major clinical trials involving coinfected patients are summarized, and drug-drug interactions between HIV antiretroviral therapy and HCV DAA therapy are discussed. Given the numbers of people at risk for primary infection and reinfection after cure, we also discuss important strategies of harm reduction and treatment as prevention. The revolution in DAAs provides the prospect of reducing the burden of liver disease, which remains one of the leading causes of death in people living with HIV. Key words: HIV-HCV coinfection; Epidemiology; Natural history; Viral interaction; Direct-acting antiviral; Drug-drug interaction