The Impact of Negative Regulation on T cell Immunity During Chronic Hepatitis C Virus Infections: A study on immunity of liver and peripheral blood

The hepatitis C virus (HCV) is very successful in establishing persistent infections by evading the immune system and predominantly infecting hepatocytes. HCV was known as non-A non-B hepatitis since the 1970’s and identified as a unique virus in 1989 1. HCV is a single-strand positive sense RNA virus belonging to the Flaviviridae family, has six major genotypes (1 to 6) and more than 100 subtypes have been identified. The single ~9600 nucleotide RNA molecule carries one open reading frame encoding for the structural proteins core, envelope 1 (E1), envelope 2 (E2), p7, and 6 non-structural proteins (NS) needed for replication (NS2, NS3, NS4a, NS4b, NS5a and NS5b). The current model of HCV infection suggests that after entering circulation, HCV is transported to the liver via lipoproteins where HCV binds to low density lipoprotein receptors, and possibly DC-sign and other receptors on hepatocytes, followed by viral entry in a clathrin-dependent endocytic process requiring interaction between the viral envelope with cell surface tetraspanin CD81, scavenger receptor type B class I, and the tight junction proteins claudin-1 and occludin (reviewed in 2). Controversy exists whether HCV directly impairs immune cell functions by infecting these cells. However, following infection, innate immunity and the HCV-specific immune response mediated via T cells are functionally impaired, and unable to eliminate the HCV in the majority of individuals 3-6. Only a minority of infected patients are able to clear HCV spontaneously, and about 80% develop a chronic infection with viral replication primarily occurring in the liver 7. It is estimated that globally 120 to 170 million patients are persistently infected with HCV

Immune activation in prolonged cART-suppressed HIV patients is comparable to that of healthy controls

Sustained immune activation during chronic HIV infection is considered to augment co-morbidity and mortality. Effective combination antiretroviral therapy (cART) has shown to dampen immune activation especially during the first year cART, but the effects of long-term cART in patients without major comorbidities remains under-investigated. We performed a comprehensive analysis including cellular, intracellular and plasma biomarkers to study the effect of cART on immune parameters in 5 groups of 10 HIV patients. All patients were without major co-morbidities and grouped based on cART duration (0, 1, 3, 5, and 10 years). We included 10 matched healthy controls for comparison. Our data show that after the first year of cART, no additional effect on the level of inflammatory markers is observed in HIV infected patients without major co morbidities. Residual immune activation status in well-treated HIV-infection is similar to levels observed in healthy controls

Negative Regulation of Hepatitis C Virus Specific Immunity Is Highly Heterogeneous and Modulated by Pegylated Interferon-Alpha/Ribavirin Therapy

Specific inhibitory mechanisms suppress the T-cell response against the hepatitis C virus (HCV) in chronically infected patients. However, the relative importance of suppression by IL-10, TGF-β and regulatory T-cells and the impact of pegylated interferon-alpha and ribavirin (PegIFN-α/ribavirin) therapy on these inhibitory mechanisms are still unclear. We revealed that coregulation of the HCV-specific T-cell responses in blood of 43 chronic HCV patients showed a highly heterogeneous pattern before, during and after PegIFN-α/ribavirin. Prior to treatment, IL-10 mediated suppression of HCV-specific IFN-γ production in therapy-naive chronic HCV patients was associated with higher HCV-RNA loads, which suggests that protective antiviral immunity is controlled by IL-10. In addition, as a consequence of PegIFN-α/ribavirin therapy, negative regulation of especially HCV-specific IFN-γ production by TGF-β and IL-10 changed dramatically. Our findings emphasize the importance of negative regulation for the dysfunctional HCV-specific immunity, which should be considered in the design of future immunomodulatory therapies

Mucosal-associated invariant T-cell frequency and function in blood and liver of HCV mono- and HCV/HIV co-infected patients with advanced fibrosis

__Background & Aims:__ Mucosal-associated invariant T (MAIT) cells are important innate T cells with antimicrobial and immunoregulatory activity, recently found to be depleted in blood of patients with HIV and HCV mono-infections. In this study, we assessed the impact of HIV, HCV and HCV/HIV co-infection on circulating and intrahepatic MAIT-cells and correlations with liver fibrosis. __Methods:__ In this cross-sectional study, nine healthy subjects, nine HIV, 20 HCV and 22 HCV/HIV co-infected patients were included. Blood and liver fine needle aspirate biopsies were studied using flowcytometry for CD3+CD161+Vα7.2+ MAIT-cell frequency, phenotype and function in HCV mono-infected and HCV/HIV co-infected patients without or with mild fibrosis (Metavir-score F0-F1) or severe fibrosis to cirrhosis (Metavir-score F3-F4). __Results:__ Circulating MAIT-cells were decreased in blood of HCV, HIV and HCV/HIV patients with F0-F1. In HCV/HIV co-infected individuals with severe fibrosis to cirrhosis, the frequency of circulating MAIT-cells was even further depleted, whereas their function was comparable to HCV/HIV co-infected patients with low or absent fibrosis. In contrast, in HCV mono-infected patients, MAIT-cell frequencies were not related to fibrosis severity; however, MAIT-cell function was impaired in mono-infected patients with more fibrosis. More advanced liver fibrosis in HCV or HCV/HIV-infected patients was not reflected by increased accumulation of MAIT-cells in the affected liver. __Conclusions:__ Severe liver fibrosis is associated with dysfunctional MAIT-cells in blood of HCV mono-infected patients, and lower MAIT frequencies in blood of HCV/HIV co-infected patients, without evidence for accumulation in the liver

Frequencies of circulating MAIT cells are diminished in chronic hCV, HIV and HCV/ HIV Co-Infection and do not recover during therapy

Objective Mucosal-associated invariant T (MAIT) cells comprise a subpopulation of T cells that can be activated by bacterial products and cytokines to produce IFN-γ. Since little is known on MAIT cells during HCV infection, we compared their phenotype and function in comparison to HIV and HCV/HIV co-infected patients, and determined the effect of IFN-α-based and direct-acting antiviral therapy on MAIT cells of HCV patients. Methods Blood samples from patients with chronic HCV (CHCV), virologically suppressed HIV, acute HCV/HIV co-infection (AHCV/HIV) and healthy individuals were examined by flowcytometry for phenotype and function of MAIT and NK cells. Results and Conclusions Compared to healthy individuals, the frequency of CD161+ Vα7.2+ MAIT cells was significantly decreased in patients with CHCV, HIV and AHCV/HIV co-infection. CD38 expression on MAIT cells was increased in AHCV/HIV patients. MAIT cells were responsive to IFN-α in vitro as evidenced by enhanced frequencies of IFN-γ producing cells. IFN-α-based therapy for CHCV decreased the frequency of IFN-γ+ MAIT cells, which was still observed 24 weeks after successful therapy. Importantly, even after successful IFN-α-based as well as IFN-αfree therapy for CHCV, decreased frequencies of MAIT cells persisted. We show that the frequencies of MAIT cells are reduced in blood of patients with CHCV, HIV and in AHCV/ HIV co-infection compared to healthy individuals. Successful therapy for CHCV did not normalize MAIT cell frequencies at 24 weeks follow up. The impact of HIV and HCV infection on the numbers and function of MAIT cells warrant further studies on the impact of viral

Declining Hepatitis C Virus (HCV) Incidence in Dutch Human Immunodeficiency Virus-Positive Men Who Have Sex With Men After Unrestricted Access to HCV Therapy

Background Direct-acting antivirals (DAAa) cure hepatitis C virus (HCV) infections in 95% of infected patients. Modeling studies predict that universal HCV treatment will lead to a decrease in the incidence of new infections but real-life data are lacking. The incidence of HCV among Dutch human immunodeficiency virus (HIV)–positive men who have sex with men (MSM) has been high for >10 years. In 2015 DAAs became available to all Dutch HCV patients and resulted in a rapid treatment uptake in HIV-positive MSM. We assessed whether this uptake was followed by a decrease in the incidence of HCV infections. Methods Two prospective studies of treatment for acute HCV infection enrolled patients in 17 Dutch HIV centers, having 76% of the total HIV-positive MSM population in care in the Netherlands. Patients were recru

Gene expression profiling to predict and assess the consequences of therapy-induced virus eradication in chronic hepatitis C virus infection

Systems biology has proven to be a powerful tool to identify reliable predictors of treatment response in chronic hepatitis C virus (HCV) infection. In the present study, we studied patients with chronic HCV infection who responded to interferon (IFN)-based therapy, as evidenced by an absence of HCV RNA at the end of treatment, and focused on two issues that have not received much attention. First, we evaluated whether specific genes or gene expression patterns in blood were able to distinguish responder patients with a viral relapse from responder patients who remained virus negative after cessation of treatment. We found that patients with chronic HCV infection who were sustained responders and relapsers after IFN-based therapy showed comparable baseline clinical parameters and immune compositions in blood. However, at baseline, the gene expression profiles of a set of 18 genes predicted treatment outcome with an accuracy of 94%. Second, we examined whether patients with successful therapyinduced clearance of HCV still exhibited gene expression patterns characteristic of HCV or whether normalization of their transcriptome was observed. We observed that the relatively high expression levels of IFN-stimulated genes (ISGs) in patients with chronic HCV infection prior to therapy were reduced after successful IFN-based antiviral therapy (at 24 weeks of follow-up). These ISGs included the CXCL10, OAS1, IFI6, DDX60, TRIM5, and STAT1 genes. In addition, 1,428 differentially expressed non-ISGs were identified in paired pre- and posttreatment samples from sustained responders, which included genes involved in transforming growth factor beta (TGF-β) signaling, apoptosis, autophagy, and nucleic acid and protein metabolism. Interestingly, 1,424 genes with altered expression levels in responder patients after viral eradication were identified, in comparison to normal expression levels in healthy individuals. Additionally, aberrant expression levels of a subset of these genes, including the interleukin-32 (IL-32), IL-16, CCND3, and RASSF1 genes, were also observed at baseline. Our findings indicate that successful antiviral therapy for patients with chronic HCV infection does not lead to normalization of their blood transcriptional signature. The altered transcriptional activity may reflect HCV-induced liver damage in previously infected individuals

High treatment uptake in human immunodeficiency virus/ hepatitis C virus-coinfected patients after unrestricted access to direct-acting antivirals in the Netherlands

Background The Netherlands has provided unrestricted access to direct-acting antivirals (DAAs) since November 2015. We analyzed the nationwide hepatitis C virus (HCV) treatment uptake among patients coinfected with human immunodeficiency virus (HIV) and HCV. Methods Data were obtained from the ATHENA HIV observational cohort in which >98% of HIV-infected patients ever registered since 1998 are included. Patients were included if they ever had 1 positive HCV RNA result, did not have spontaneous clearance, and were known to still be in care. Treatment uptake and outcome were assessed. When patients were treated more than once, data were included from only the most recent treatment episode. Data were updated until February 2017. In addition, each treatment center was queried in April 2017 for a data update on DAA treatment and achieved sustained virological response. Results Of 23574 HIV-infected patients ever linked to care, 1471 HCV-coinfected patients (69% men who have sex with men, 15% persons who [formerly] injected drugs, and 15% with another HIV transmission route) fulfilled the inclusion criteria. Of these, 87% (1284 of 1471) had ever initiated HCV treatment between 2000 and 2017, 76% (1124 of 1471) had their HCV infection cured; DAA treatment results were pending in 6% (92 of 1471). Among men who have sex with men, 83% (844 of 1022) had their HCV infection cured, and DAA treatment results were pending in 6% (66 of 1022). Overall, 187 patients had never initiated treatment, DAAs had failed in 14, and a pegylated interferon-alfa–based regimen had failed in 54. Conclusions Fifteen months after unrestricted DAA availability the majority of HIV/HCV-coinfected patients in the Netherlands have their HCV infection cured (76%) or are awaiting DAA treatment results (6%). This rapid treatment scale-up may contribute to future HCV elimination among these patients