Transient liver injury associated with the early recovery of HCV-specific T-cell responses and HCV rebound in HIV-1/HCV coinfected patients undergoing highly active antiretroviral therapy

Evaluation of Clinical Biomarkers Related to CD4 Recovery in HIV-Infected Patients—5-Year Observation

Human Immunodeficiency Virus infection leads to the impairment of immune system function. Even long-term antiretroviral therapy uncommonly leads to the normalization of CD4 count and CD4:CD8 ratio. The aim of this study was to evaluate possible clinical biomarkers which may be related to CD4 and CD4:CD8 ratio recovery among HIV-infected patients with long-term antiretroviral therapy. The study included 68 HIV-infected patients undergoing sustained antiretroviral treatment for a minimum of 5 years. Clinical biomarkers such as age, gender, advancement of HIV infection, coinfections, comorbidities and applied ART regimens were analyzed in relation to the rates of CD4 and CD4:CD8 increase and normalization rates. The results showed that higher rates of CD4 normalization are associated with younger age (p = 0.034), higher CD4 count (p = 0.034) and starting the therapy during acute HIV infection (p = 0.012). Higher rates of CD4:CD8 ratio normalization are correlated with higher CD4 cell count (p = 0.022), high HIV viral load (p = 0.006) and acute HIV infection (p = 0.013). We did not observe statistically significant differences in CD4 recovery depending on gender, HCV/HBV coinfections, comorbidities and opportunistic infections. The obtained results advocate for current recommendations of introducing antiretroviral therapy as soon as possible, preferably during acute HIV infection, since it increases the chances of sufficient immune reconstruction.

The dynamics of HCV-specific antibody responses in HIV/HCV patients on long-term antiretroviral therapy

Antibody responses have not been fully characterised in chronically HIV/HCV patients receiving antiretroviral therapy (ART). Seventeen HIV/HCV patients receiving ART were followed for a median (range) interval of 597 (186-766) weeks. Prior to ART, HIV/HCV patients had lower levels of antibodies reactive with HCV core and JFH-1, and lower genotype cross-reactive neutralising antibodies (nAb) titres, than HCV patients. Levels of JFH-1 reactive antibody increased on ART, irrespective of CD4⁺ T-cell counts or changes in serum ALT levels. The appearance of nAb coincided with control of HCV viral replication in five HIV/HCV patients. In other patients, HCV viral loads remained elevated despite nAb responses. Sustained virological responses following HCV therapy were associated with reduced antibody responses to JFH-1 and core but elevated responses to non-structural proteins. We conclude that nAb responses alone may fail to clear HCV, but contribute to control of viral replication in some HIV/HCV patients responding to ART.

Increased proportions of dendritic cells and recovery of IFNγ responses in HIV/HCV co-infected patients receiving ART

Dendritic cell (DC) numbers and functions can be affected by HIV and HCV disease, but the effects of antiretroviral therapy (ART) on DC and the implications of these changes are unclear. We examined circulating DC in samples from Indonesian patients beginning ART with advanced HIV disease and documented mild/moderate HCV hepatitis. Frequencies of myeloid and plasmacytoid DC increased after 6 months on ART, but frequencies of DC producing IL-12 or IFNα following stimulation with TLR agonists (CL075, CpG) did not change. IFNγ responses to CL075, HCV and other antigens rose over this period. Hence increased IFNγ responses during ART may be associated with increased DC frequencies rather than changes in their functional capacity.

Modulation of HCV replication after combination antiretroviral therapy in HCV/HIV co-infected patients

The hepatitis C virus (HCV) is an important contributor to morbidity and mortality in patients co-infected with HIV. Co-infection results in increased HCV replication and more rapid rates of liver disease progression. The effect of HIV combination antiretroviral therapy (cART) on HCV replication has not been studied in depth. To address this issue, we enrolled a small cohort of HCV/HIV co-infected patients into a cART initiation trial and used dynamic modeling combined with evaluation of immune responses and microarray profiles to determine how effective treatment of HIV affects HCV. Treatment with cART resulted in increased HCV replication and increased alanine aminotransferase (ALT) in a subset of patients. Subjects with evidence of hepatic injury (increased ALT) were more likely to have HCV-specific immune responses directed against HCV epitopes. Over time, HCV viral loads declined. Reproducible and biologically important gene expression changes occurred in co-infected patients who underwent successful cART. The effective suppression of HIV by cART initiated a cascade of early and late events in treated patients. Early events involving down-regulation of interferon-stimulated genes may have led to transiently increased viral replication and hepatic injury. At later time points, HCV viral load declined to levels comparable to those seen in the setting of HCV monoinfection. These findings support early antiretroviral therapy in those with HCV/HIV co-infection.

Patients co-infected with hepatitis C virus (HCV) and human immunodeficiency virus recover genotype cross-reactive neutralising antibodies to HCV during antiretroviral therapy

When severely immunodeficient HIV/HCV co-infected patients are treated with antiretroviral therapy, it is important to know whether HCV-specific antibody responses recover and whether antibody profiles predict the occurrence of HCV-associated immune restoration disease (IRD). In 50 HIV/HCV co-infected patients, we found that antibody reactivity and titres of neutralising antibodies (nAb) to JFH-1 (HCV genotype 2a virus) increased over 48 weeks of therapy. Development of HCV IRD was associated with elevated reactivity to JFH-1 before and during the first 12 weeks of therapy. Individual analyses of HCV IRD and non-HCV IRD patients revealed a lack of an association between nAb responses and HCV viral loads. These results showed that increased HCV-specific antibody levels during therapy were associated with CD4(+) T-cell recovery. Whilst genotype cross-reactive antibody responses may identify co-infected patients at risk of developing HCV IRD, neutralising antibodies to JFH-1 were not involved in suppression of HCV replication during therapy.

Antiretroviral therapy, interferon sensitivity, and virologic setpoint in human immunodeficiency virus/hepatitis C virus coinfected patients

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) cause substantial mortality, especially in persons chronically infected with both viruses. HIV infection raises plasma HCV RNA levels and diminishes the response to exogenous alpha interferon (IFN). The degree to which antiretroviral therapy (ART) control of infection overcomes these HIV effects is unknown. Participants with HIV-HCV coinfection were enrolled in a trial to measure HCV viral kinetics after IFN administration (ΔHCVIFN ) twice: initially before (pre-ART) and then after (post-ART) HIV RNA suppression. Liver tissue was obtained 2-4 hours before each IFN injection to measure interferon stimulated genes (ISGs). Following ART, the ΔHCVIFN at 72 hours (ΔHCVIFN,72 ) increased in 15/19 (78.9%) participants by a median (interquartile range [IQR]) of 0.11 log10 IU/mL (0.00-0.40; P < 0.05). Increases in ΔHCVIFN,72 post-ART were associated with decreased hepatic expression of several ISGs (r = -0.68; P = 0.001); a 2-fold reduction in a four-gene ISG signature predicted an increase in ΔHCVIFN,72 of 0.78 log10 IU/mL (95% confidence interval [CI] 0.36,1.20). Pre- and post-ART ΔHCVIFN,72 were closely associated (r = 0.87; P < 0.001). HCV virologic setpoint also changed after ART (ΔHCVART ): transient median increases of 0.28 log10 IU/mL were followed by eventual median decreases from baseline of 0.21 log10 IU/mL (P = 0.002). A bivariate model of HIV RNA control (P < 0.05) and increased expression of a nine-gene ISG signature (P < 0.001) predicted the eventual decreased ΔHCVART .

CONCLUSION

ART is associated with lower post-IFN HCV RNA levels and that change is linked to reduced hepatic ISG expression. These data support recommendations to provide ART prior to IFN-based treatment of HCV and may provide insights into the pathogenesis of HIV-HCV coinfection.

Recombinant HCV core protein and the secretion of associated cytokines (IL-6, TNF-α and IFN-γ) in immunized mice

Hepatitis C virus (HCV) is an important cause of acute and chronic hepatitis which is a disorder with a high worldwide prevalence. HCV core protein was considered as immunogenic counterpart of the HCV vaccine and it is an ideal candidate for HCV vaccine. Since cytokines such as IL-6, TNF-alpha and IFN-Gamma are responsible for the prevention of viral infection, this study aimed to evaluate the effectiveness of HCV core protein as a vaccine. Ten BALB/c mice were immunized with HCV core protein and after 42 days the splenocytes were isolated and the IL-6 and INF-gamma secretion were measured using ELISpot technique, at the same time TNF-alpha was determined by ELISA in the sera. The MTT assay was done to assess the viability of the cultured splenocytes. For evaluating the humoral immune response against the recombinant HCV core protein the DOT Blot test was used. Data was compared using one-way ANOVA test and significant results were considered at p < 0.05. In the present study the IL-6, INF-gamma and TNF-alpha levels were dramatically higher in the immunized mice compared to the control group (respectively, 22.9 +/- 1.26; 18.53 +/- 3.87; 53.96 +/- 4.54 and p < 0.05). The immunized mice with recombinant HCV core protein showed higher amount of IL-6, INF-gamma and TNF-alpha in the current study. Since the level of IL-6, TNF-alpha and IFN-gamma is high in patients with acute HCV infection, thus a vaccine which could stimulate the secretion of these cytokines in advance may have a preventive role.

HIV and co-infections

Despite significant reductions in morbidity and mortality secondary to availability of effective combination anti-retroviral therapy (cART), human immunodeficiency virus (HIV) infection still accounts for 1.5 million deaths annually. The majority of deaths occur in sub-Saharan Africa where rates of opportunistic co-infections are disproportionately high. In this review, we discuss the immunopathogenesis of five common infections that cause significant morbidity in HIV-infected patients globally. These include co-infection with Mycobacterium tuberculosis, Cryptococcus neoformans, hepatitis B virus, hepatitis C virus, and Plasmodium falciparum. Specifically, we review the natural history of each co-infection in the setting of HIV, the specific immune defects induced by HIV, the effects of cART on the immune response to the co-infection, the pathogenesis of immune restoration disease (IRD) associated with each infection, and advances in the areas of prevention of each co-infection via vaccination. Finally, we discuss the opportunities and gaps in knowledge for future research.