Residual Immune Activation and Latency

The introduction of combination antiretroviral therapy (cART) in the 1990s has dramatically changed the course of HIV infection, decreasing the risk for both AIDS- and non-AIDS-related events. Cancers, cardiovascular disease (CVD), liver and kidney disease, neurological disorders and frailty have become of great importance lately in the clinical management as they represent the principal cause of death in people living with HIV who receive cART (Kirk et al. in Clin Infect Dis 45(1):103-10, 2007; Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006; Ances et al. J Infect Dis 201(3):336-340, 2010; Desquilbet et al. J Gerontol A Biol Sci Med Sci 62(11):1279-1286, 2007; Lifson et al. HIV Clin Trials 9(3):177-185, 2008). Despite the undeniable achievements of cART, we are now faced with its limitations: a considerable proportion of individuals, referred as to immunological non-responders, fails to reconstitute the immune system despite optimal treatment and viral suppression (Kelley et al. Clin Infect Dis 48(6):787-794, 2009; Robbins et al. Clin Infect Dis 48(3):350-361, 2009) and remains at high risk for opportunistic infections and non-AIDS-related events (Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006). Moreover, the generalized state of immune activation and inflammation, linked to serious non-AIDS events, persists despite successful HIV suppression with cART. Finally, the current strategies have so far failed to eradicate the virus, and inflammation appears a driving force in viral persistence. In the light of all this, it is of fundamental importance to investigate the pathophysiological processes that link incomplete immune recovery, immune activation and HIV persistence to design targeted therapies that could impact on the three.

Virologic and immunologic aspects of HIV-hepatitis C virus coinfection

HIV/hepatitis C virus (HCV) coinfection is estimated to affect 2 million individuals globally. The acceleration of HCV-associated complications, particularly hepatic fibrosis, because of HIV coinfection has been well established, whereas the impact of HCV on HIV progression remains unclear. In this review, we summarize the current evidence on the impact of coinfection on the transmission and clinical progression of each infection. We focus on the virological and immunological alterations that contribute to HIV and HCV pathogenesis in coinfection and also review the disease-modifying effects of antiretroviral therapy as they pertain to HCV.

Why is viral eradication so important in patients with HCV-related cirrhosis?

Approximately one-third of patients infected with chronic HCV have cirrhosis, and this is likely to increase in the near future. The risk of complications, mainly the development of hepatocellular carcinoma, depends on the presence of cirrhosis, and a significant increase in the incidence of cirrhosis-related events, including mortality, is likely in the following years. All-oral therapy with direct-acting antivirals (DAAs) offers a safe and short treatment, with cure rates over 90% in compensated cirrhosis. Cirrhotic patients should be given high priority for treatment because viral clearance has a significant impact on the natural history of HCV infection, halting the progression of the disease and inducing the regression of fibrosis, as well as reducing the need for liver transplantation and improving survival. The benefit of DAAs is great in patients with decompensated cirrhosis, up until recently a population for whom no alternative therapy was available. The efficacy of all-oral therapy has been reported to improve liver function in about 50% of Child-Pugh class C patients. The regression of cirrhosis observed in more than half of patients achieving viral eradication on prior interferon-based regimens still has to be demonstrated in patients treated with DAAs, although there is reason to believe that this will happen. Advanced cirrhosis will eventually become the last boundary of antiviral therapy that will soon be conquered with new drugs currently pending approval.

Antiretroviral therapy and liver disease progression in HIV and hepatitis C co-infected patients: a systematic review and meta-analysis

Background

HIV co-infection exacerbates hepatitis C disease, increasing the risk of cirrhosis and hepatitis C-related mortality. Combination antiretroviral therapy (cART) is the current standard treatment for co-infected individuals, but the impact of cART and antiretroviral (ARV) monotherapy on liver disease in this population is unclear. We aimed to assess the effect of cART and ARV monotherapy on liver disease progression and liver-related mortality in individuals co-infected with HIV and chronic hepatitis C.

Methods

A systematic review with meta-analyses was conducted. MEDLINE and EMBASE bibliographic databases were searched up to September 2015. Study quality was assessed using a modified Newcastle-Ottawa scale. Results were synthesised narratively and by meta-analysis.

Results

Fourteen observational studies were included. In analyses that adjusted for potential confounders, risk of liver-related mortality was significantly lower in patients receiving cART (hazard ratio/odds ratio 0.31, 95 % CI 0.14 to 0.70). Results were similar in unadjusted analyses (relative risk 0.40, 95 % CI 0.29 to 0.55). For outcomes where meta-analysis could not be performed, results were less consistent. Some studies found cART was associated with lower incidence of, or slower progression of liver disease, fibrosis and cirrhosis, while others showed no evidence of benefit. We found no evidence of liver-related harm from cART or ARV monotherapy compared with no HIV therapy.

Conclusions

cART was associated with significantly lower liver-related mortality in patients co-infected with HIV and HCV. Evidence of a positive association between cART and/or ARV monotherapy and liver-disease progression was less clear, but there was no evidence to suggest that the absence of antiretroviral therapy was preferable.

Electronic supplementary material

The online version of this article (doi:10.1186/s41124-016-0015-7) contains supplementary material, which is available to authorized users.

Hepatitis C virus-HIV-coinfected patients and liver transplantation

PURPOSE OF REVIEW

To review the experience to date and unique challenges associated with liver transplantation in hepatitis C virus (HCV)/HIV-coinfected patients.

RECENT FINDINGS

The prevalence of cirrhosis and hepatocellular carcinoma is rising among HIV-infected individuals. With careful patient selection and in the absence of HCV infection, HIV-infected and HIV-uninfected liver transplant recipients have comparable posttransplant outcomes. However, in the presence of HCV infection, patient and graft survival are significantly poorer in HIV-infected recipients, who have a higher risk of aggressive HCV recurrence, acute rejection, sepsis, and multiorgan failure. Outcomes may be improved with careful recipient and donor selection and with the availability of new highly potent all-oral HCV direct acting antivirals (DAAs). Although all-oral DAAs have not been evaluated in HIV/HCV-coinfected transplant patients, HIV does not adversely impact treatment success in nontransplant populations. Therefore, there is great hope that HCV can be successful eradicated in HIV/HCV-coinfected transplant patients and will result in improved outcomes. Careful attention to drug-drug interactions with HIV antiretroviral agents, DAAs, and posttransplant immunosuppressants is required.

SUMMARY

Liver transplant outcomes are poorer in HIV/HCV-coinfected recipients compared with those with HCV-monoinfection. The new HCV DAAs offer tremendous potential to improve outcomes in this challenging population.

CD4 recovery on antiretroviral therapy is associated with decreased progression to liver disease among hepatitis C virus-infected injecting drug users

Background.  Human immunodeficiency virus (HIV) coinfection accelerates liver disease progression in individuals with chronic hepatitis C. We evaluated the associations of CD4, HIV RNA, and antiretroviral therapy (ART)-induced CD4 recovery with liver diagnoses in a prospective cohort of injecting drug users (IDUs). Methods.  We evaluated 383 coinfected IDUs in the Boston area, prospectively observed for a median of 1.8 years. Liver disease progression included the first occurrence of hepatocellular carcinoma, variceal bleeding, ascites, encephalopathy, or death due to hepatic failure. Multivariable-adjusted extended Cox models were specified to estimate hazard ratios (HRs) for comparisons of CD4, change in CD4 (from nadir), and HIV RNA with respect to liver disease progression events. Results.  Twenty-four persons experienced a liver disease progression event over 1155 person-years (2.1 per 100 person-years), including 20 deaths attributed to end-stage liver disease (1.7 per 100 person-years). CD4 at baseline and over follow-up strongly predicted liver disease progression (baseline CD4 <200 vs ≥200: HR = 5.23, 95% confidence interval [CI], 2.30-11.92; time-updated CD4 <200 vs ≥200: HR = 11.79, 95% CI, 4.47-31.07). Nadir CD4 was also a strong indicator (<100 vs ≥100: HR = 3.52, 95% CI, 1.54-8.06). A lack of CD4 recovery (failure to increase 100 cells over nadir) among ART initiators was associated with increased risk (HR = 7.69; 95% CI, 2.60-22.69). Human immunodeficiency virus RNA was not significantly associated with liver disease progression. Conclusions.  Impaired immune function was highly predictive of liver disease progression in this cohort of IDUs, and a lack of CD4 recovery on ART was associated with increased risk of progression to HCV-associated liver disease.

HCV and HIV co-infection: mechanisms and management

HCV and HIV co-infection is associated with accelerated hepatic fibrosis progression and higher rates of liver decompensation and death compared to HCV monoinfection, and liver disease is a leading cause of non-AIDS-related mortality among HIV-infected patients. New insights have revealed multiple mechanisms by which HCV and HIV lead to accelerated disease progression, specifically that HIV infection increases HCV replication, augments HCV-induced hepatic inflammation, increases hepatocyte apoptosis, increases microbial translocation from the gut and leads to an impairment of HCV-specific immune responses. Treatment of HIV with antiretroviral therapy and treatment of HCV have independently been shown to delay the progression of fibrosis and reduce complications from end-stage liver disease among co-infected patients. However, rates of sustained virologic response with PEG-IFN and ribavirin have been significantly inferior among co-infected patients compared with HCV-monoinfected patients, and treatment uptake has remained low given the limited efficacy and tolerability of current HCV regimens. With multiple direct-acting antiviral agents in development to treat HCV, a unique opportunity exists to redefine the treatment paradigm for co-infected patients, which incorporates data on fibrosis stage as well as potential drug interactions with antiretroviral therapy.