Baseline levels of soluble CD14 and CD16+56- natural killer cells are negatively associated with response to interferon/ribavirin therapy during HCV-HIV-1 coinfection

CD56- CD16+ NK cells from HIV-infected individuals negatively regulate IFN-γ production by autologous CD8+ T cells

The percentage of human CD56^- CD16⁺ NK cells increases during chronic infection with human HIV; however, the biologic role of CD56^- CD16⁺ NK cells in HIV infection is unclear. Our results demonstrate that the percentage of CD56^- CD16⁺ NK cells producing IL-10 and TGF-β was higher than CD56^dim CD16⁺ NK cells. CD56^- CD16⁺ NK cells could inhibit IFN-γ production by autologous CD8⁺ T cells, and this inhibition could be partially reversed by anti-IL-10, anti-TGF-β, or anti-PD-L1 mAbs. CD56^- CD16⁺ NK cells are potential targets for the development of novel immune therapies against HIV infection.

Brief Report: CD14brightCD16- monocytes and sCD14 level negatively associate with CD4-memory T-cell frequency and predict HCV-decline on therapy

During HIV+ hepatitis C virus (HCV)+ coinfection CD14CD16 monocytes produce soluble immune-activation markers that predict disease progression and poor response to interferon (IFN)-α treatment. We evaluated relationships among immune activation, monocyte phenotype, CD4-memory T cells, and HCV-, cytomegalovirus-, and cytomegalovirus/Epstein-Barr virus/influenza-specific IFN-γ-response before and during IFN-α treatment. Effector-memory and central-memory CD4 T-cell frequencies were lower in HCV+ HIV+ donors than in uninfected donors and correlated negatively with HCV level, CD14CD16 monocytes, and plasma sCD14. sCD14 and CD14CD16 monocytes negatively correlated with IFN-α-dependent HCV decline. CD4 effector-memory T cells positively associated with cytomegalovirus/Epstein-Barr virus/influenza(CEF)-specific IFN-γ response, while sCD14 negatively associated with both CD4 effector-memory T cells and CEF-specific IFN-γ response. These data support a role for memory-CD4 T cells in HCV containment and link immune activation and CD14CD16-monocyte frequency to the failure of IFN-dependent HCV clearance.

Hepatitis C Virus and Human Cytomegalovirus-Natural Killer Cell Subsets in Persistent Viral Infections

Hepatitis C virus (HCV) and human cytomegalovirus (HCMV) are prominent examples of RNA and DNA viruses, respectively, that establish a persistent infection in their host. HCV affects over 185 million patients worldwide, who are at high risk for developing liver fibrosis, liver cirrhosis, and ultimately hepatocellular carcinoma. Recent breakthroughs in HCV therapy, using direct-acting antivirals have provided the opportunity to monitor natural killer (NK) cells after clearance of a chronic infection. There is now increasing evidence that the individual NK cell repertoire before infection is predictive for the course of disease. HCMV affects the majority of the global population. While being asymptomatic in healthy individuals, HCMV represents a severe clinical challenge in immunocompromised patients. Both viral infections, HCV and HCMV, lead to long-lasting and profound alterations within the entire NK cell compartment. This review article, will discuss the diverse range of changes in the NK cell compartment as well as potential consequences for the course of disease.

During Hepatitis C Virus (HCV) Infection and HCV-HIV Coinfection, an Elevated Plasma Level of Autotaxin Is Associated With Lysophosphatidic Acid and Markers of Immune Activation That Normalize During Interferon-Free HCV Therapy

BACKGROUND

 Immune activation predicts morbidity during hepatitis C virus (HCV) infection and human immunodeficiency virus (HIV) infection, although mechanisms underlying immune activation are unclear. Plasma levels of autotaxin and its enzymatic product, lysophosphatidic acid (LPA), are elevated during HCV infection, and LPA activates immunocytes, but whether this contributes to immune activation is unknown.

METHODS

 We evaluated plasma levels of autotaxin, interleukin 6 (IL-6), soluble CD14 (sCD14), soluble CD163 (sCD163), and Mac2 binding protein (Mac2BP) during HCV infection, HIV infection, and HCV-HIV coinfection, as well as in uninfected controls, before and after HIV antiretroviral therapy (ART) initiation and during interferon-free HCV therapy.

RESULTS

 We observed greater plasma autotaxin levels in HCV-infected and HCV-HIV-coinfected participants, compared with uninfected participants, primarily those with a higher ratio of aspartate aminotransferase level to platelet count. Autotaxin levels correlated with IL-6, sCD14, sCD163, Mac2BP, and LPA levels in HCV-infected participants and with Mac2BP levels in HCV-HIV-coinfected participants, while in HIV-infected individuals, sCD14 levels correlated with Mac2BP levels. Autotaxin, LPA, and sCD14 levels normalized, while sCD163 and Mac2BP levels partially normalized within 6 months of starting interferon-free HCV therapy. sCD163 and IL-6 levels normalized within 6 months of starting ART for HIV infection. In vitro, LPA activated monocytes.

CONCLUSIONS

 These data indicate that elevated levels of autotaxin and soluble markers of immune activation during HCV infection are partially reversible within 6 months of initiating interferon-free HCV treatment and that autotaxin may be causally linked to immune activation during HCV infection and HCV-HIV coinfection.

Natural killer cells in hepatitis C: Current progress

Patients infected with the hepatitis C virus (HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairment of HCV-specific T cells is associated with the evolution of an acute infection to chronic hepatitis. While T cells are the important effector cells in adaptive immunity, natural killer (NK) cells are the critical effector cells in innate immunity to virus infections. The findings of recent studies on NK cells in hepatitis C suggest that NK cell responses are indeed important in each phase of HCV infection. In the early phase, NK cells are involved in protective immunity to HCV. The immune evasion strategies used by HCV may target NK cells and might contribute to the progression to chronic hepatitis C. NK cells may control HCV replication and modulate hepatic fibrosis in the chronic phase. Further investigations are, however, needed, because a considerable number of studies observed functional impairment of NK cells in chronic HCV infection. Interestingly, the enhanced NK cell responses during interferon-α-based therapy of chronic hepatitis C indicate successful treatment. In spite of the advances in research on NK cells in hepatitis C, establishment of more physiological HCV infection model systems is needed to settle unsolved controversies over the role and functional status of NK cells in HCV infection.

Low levels of microbial translocation marker LBP are associated with sustained viral response after anti-HCV treatment in HIV-1/HCV co-infected patients

BACKGROUND

Microbial translocation (MT) contributes to immune activation during HIV and HCV infections. We investigated the kinetics of MT markers during anti-HCV and anti-HIV treatments, and if baseline plasma levels of lipopolysaccharide (LPS), lipopolysaccharide binding protein (LBP) and soluble CD14 (sCD14) could predict anti-HCV treatment outcome.

METHODS

Plasma from 78 HIV-infected patients was evaluated for LPS, LBP and sCD14. The patients starting anti-HCV treatment (with ongoing antiretroviral (ART) treatment) were categorized into sustained viral responders (SVR; n = 21) or non-responders (NR; n = 15) based on treatment outcome. ART starting subjects--were categorized into chronically HCV-infected (CH; n = 24) and mono-infected (HIV; n = 18), based on the HCV infection status. Samples were collected before start (at baseline) of pegylated-interferon-alpha/ribavirin (peg-IFN/RBV) or antiretroviral-therapy and two years after treatment start (at follow up). χ2-test, non-parametric statistics and logistic regression were applied to determine the associations with treatment response and changes of the soluble markers.

RESULTS

Plasma levels of LPS and sCD14 were elevated in all subjects before antiviral-treatment but remained unchanged at follow-up. Elevated levels of LBP were present in patients with HIV and HIV/HCV co-infection and were reduced by ART. Additionally, higher levels of LBP were present at baseline in NR vs. SVR. Higher levels of LBP at baseline were associated with non-response to peg-IFN/RBV treatment in both bivariate (OR: 0.19 95% CI: 0.06-0.31, p = 0.004) and multivariate analysis (OR: 1.43, 95% CI: 1.1-1.86, p = 0.07).

CONCLUSION

In HIV/HCV co-infected patients high baseline LBP levels are associated with non-response to peg-IFN/RBV therapy. Plasma LBP (decreased by ART) may be a more relevant MT marker than LPS and sCD14.

The dynamic relationship between innate immune biomarkers and interferon-based treatment effects and outcome in hepatitis C virus infection is altered by telaprevir

Soluble CD14 (sCD14) and IL-18 are markers and mediators of the innate immune response, and their plasma levels candidate biomarkers of HCV treatment effects and outcome. Here, we retrospectively studied sCD14 and IL-18 over the course of interferon-based treatment of HCV genotype 1 infection, with the aim to investigate the impact of direct-acting antivirals (DAAs) on the dynamics and relationships between these biomarkers and treatment effects and outcome. Two cohorts were followed longitudinally; one treated with standard dual therapy of pegylated IFNα and ribavirin, and one cohort receiving triple therapy including Telaprevir. sCD14 and IL-18 were measured before and during treatment and analyzed in relation to treatment effects. The initial analysis confirmed two patterns previously observed in patients with HCV/HIV-1 co-infection: Baseline levels of sCD14 were significantly lower in patients that went on to clear HCV infection in response to IFNα and ribavirin, and sCD14 levels were strongly induced during the course of this treatment. Interestingly, baseline levels of sCD14 and IL-18 in combination predicted treatment outcome in dual therapy better than either marker alone. Notably, these associations were weaker with the addition of Telaprevir to the treatment regimen, suggesting that the relationships between innate immune activation and outcome were altered and diminished by inclusion of a DAA in the treatment. In triple therapy, the dynamic increase of sCD14 in response to treatment was higher in patients clearing the virus, suggesting that the innate response to interferon is still significantly associated with outcome in patients treated with DAA-containing regimens. These results support the notion that levels of innate immune activation before and during treatment are associated with interferon-based treatment outcome. Furthermore, the addition of Telaprevir significantly alters the dynamics and relationships between innate immune biomarkers and treatment effects and outcome.

Validation of TaqMan® SNP genotyping specificity for rs12979860 of IL-28B: modeling primer specificity in vitro

Members of the type III interferon gene family arose by gene duplication events and have retained a high percent identity both in their coding and non-coding regions. In this study, the specificity of a widely used TaqMan(®) SNP genotyping assay for rs12979860 is validated. The 66 bp template for SNP genotyping has only 3 bp at one 5' end that vary between IL-28B and IL-28A; excluding the rs12979860 SNP itself. Conflicting annealing temperatures were found for the mismatched 19 bp primer to IL-28B and IL-28A with in silico melting temperature algorithms, or with in vitro dissociation curves. In order to prove specificity for IL-28B, an in vitro competition assay was setup with genomic DNA and synthetic oligonucleotides. When genomic DNA, containing equimolar concentrations of rs12979860 and the homologous region of IL-28A are present, no off-target amplification was observed. This SNP genotyping assay is therefore specific for rs12979860 and all previously reported results are valid. Finally, using a completely synthetic in vitro competition assay it was possible to calculate the amount of off-target template that will produce 1/2 the maximum on-target (VIC) fluorescent signal, a value that is between a C/C genotype and a T/T genotype. This value is defined in the manuscript as the half maximum positive value, KHPV, and in the present assay KHPV is 15.75±0.0721, represented as the relative fold increase in the amount of IL-28A over rs12979860. This method will be of interest to those performing genotyping on highly conserved gene families.

Interleukin-27 is differentially associated with HIV viral load and CD4+ T cell counts in therapy-naïve HIV-mono-infected and HIV/HCV-co-infected Chinese

Human Immunodeficiency Virus (HIV) infection and the resultant Acquired Immunodeficiency Syndrome (AIDS) epidemic are major global health challenges; hepatitis C virus (HCV) co-infection has made the HIV/AIDS epidemic even worse. Interleukin-27 (IL-27), a cytokine which inhibits HIV and HCV replication in vitro, associates with HIV infection and HIV/HCV co-infection in clinical settings. However, the impact of HIV and HCV viral loads on plasma IL-27 expression levels has not been well characterized. In this study, 155 antiretroviral therapy-naïve Chinese were recruited. Among them 80 were HIV- and HCV-negative healthy controls, 45 were HIV-mono-infected and 30 were HIV/HCV-co-infected. Plasma level HIV, HCV, IL-27 and CD4+ number were counted and their correlation, regression relationships were explored. We show that: plasma IL-27 level was significantly upregulated in HIV-mono-infected and HIV/HCV-co-infected Chinese; HIV viral load was negatively correlated with IL-27 titer in HIV-mono-infected subjects whereas the relationship was opposite in HIV/HCV-co-infected subjects; and the relationships between HIV viral loads, IL-27 titers and CD4+ T cell counts in the HIV mono-infection and HIV/HCV co-infection groups were dramatically different. Overall, our results suggest that IL-27 differs in treatment-naïve groups with HIV mono-infections and HIV/HCV co-infections, thereby providing critical information to be considered when caring and treating those with HIV mono-infection and HIV/HCV co-infection.

Cellular activation and intracellular HCV load in peripheral blood monocytes isolated from HCV monoinfected and HIV-HCV coinfected patients

Background

During HCV infection, the activation status of peripheral blood monocytes and its impact on HCV replication are poorly understood. We hypothesized that a modified activation of peripheral blood monocytes in HIV-HCV coinfected compared to HCV monoinfected patients may contribute to different monocytes reservoirs of HCV replication.

Methods

We performed a case-control analysis involving HCV-infected patients with and without HIV coinfection. In peripheral blood mononuclear cells (PBMCs), peripheral blood lymphocytes (PBLs) and peripheral blood monocytes isolated from HCV monoinfected and HIV-HCV coinfected patients, intracellular HCV load and a marker of cellular activation, nuclear factor-kappaB (NF-κB) activation, were quantified using intracellular detection of HCV-core protein and electrophoretic mobility shift assay, respectively.

Results

Intracellular HCV loads were higher in monocytes isolated from HIV-HCV coinfected patients than in those of monoinfected patients. Among PBMCs isolated from HIV-HCV coinfected patients, intracellular HCV loads were higher in monocytes compared to PBLs. Cellular activation as measured by NF-κB activation was higher in monocytes isolated from HIV-HCV coinfected patients than in those of monoinfected patients.

Conclusions

Our results reveal the peripheral blood monocytes as an important extrahepatic reservoir for HCV in HIV-HCV coinfected patients and indicate a potential association between the activation state of monocytes and the size of the HCV reservoir in HIV-HCV coinfected patients.

Plasma proteome analysis reveals overlapping, yet distinct mechanisms of immune activation in chronic HCV and HIV infections

BACKGROUND

HIV infection contributes to accelerated rates of progression of liver fibrosis during hepatitis C virus (HCV) infection, and HCV liver disease contributes to mortality during HIV infection. Although mechanisms underlying these interactions are not well known, soluble and cellular markers of immune activation associate with disease progression during both infections.

METHODS

We identified proteins varying in expression across the plasma proteomes of subjects with untreated HIV infection, untreated HCV infection with low aspartate transaminase/platelet ratio index, untreated HCV infection with high aspartate transaminase/platelet ratio index, HIV-HCV coinfection, and controls. We examined correlations between dysregulated proteins and markers of immune activation to uncover biomarkers specific to disease states.

RESULTS

We observed the anticipated higher frequencies of HLA-DRCD38CD4 and CD8 T cells, higher serum soluble CD14 levels, and higher serum interleukin-6 levels for HCV- and HIV-infected groups compared with controls. Plasma proteome analysis identified 2297 peptides mapping to 227 proteins, and quantitative analysis of peptide intensity identified significant changes in 85 proteins across the 5 groups. Abundance for 7 of these proteins was validated by enzyme-linked immunosorbent assay. Forty-three of these proteins correlated with markers of immune activation, including at least 2 proteins that may directly drive T-cell activation. As a functional validation, we tested the enzymatic pathway product (lysophosphatidic acid, LPA) of one such protein, ecotonucleotide pyrophosphatase/phosphodiesterase-2, for ability to activate T cells in vitro. LPA activated T cells to express CD38 and HLA-DR.

CONCLUSIONS

These data indicate that elevated levels of ecotonucleotide pyrophosphatase/phosphodiesterase-2 and LPA during advanced HCV disease may play a role in exacerbating immune activation during HCV-HIV coinfection.

Interferon- α -Induced Changes to Natural Killer Cells Are Associated with the Treatment Outcomes in Patients with HCV Infections

Aim. We analyzed the pretreatment natural killer (NK) cell functions with the aim of predicting the sustained virological response (SVR) or the interleukin (IL) 28B polymorphism that is strongly associated with the treatment response. Methods. The peripheral NK cells from chronic hepatitis patients with HCV genotype 1 and high virus titers were activated using a Toll-like receptor (TLR) 4 ligand and IFN-α. The cell surface markers were evaluated using a flow cytometric analysis, and IFN-γ production was evaluated using an enzyme-linked immunosorbent assay (ELISA). The genotyping of the polymorphisms in the IL28B gene region (rs8099917) on chromosome 19 was performed on the DNA collected from each patient. Results. The production of IFN-γ was significantly higher in the SVR patients compared with the no-response (NR) patients, whereas the cell surface markers were similar between the SVR and the NR patients. There were no significant differences found in the IL28B genotype distribution associated with the production of IFN-γ. Conclusion. Differences in the NK cell functions were observed between the SVR patients and the NR patients, suggesting that NK cells play a potential role in the treatment response independent of the IL28B genotype.

Cardiac mitochondrial proteomic expression in inbred rat strains divergent in survival time after hemorrhage

We have previously identified inbred rat strains differing in survival time to a severe controlled hemorrhage (StaH). In efforts to identify cellular mechanisms and ultimately genes that are important contributors to enhanced STaH, we conducted a study to characterize potential differences in cardiac mitochondrial proteins in these rats. Inbred rats from three strains [Brown Norway/Medical College of Wisconsin (BN); Dark Agouti (DA), and Fawn Hooded Hypertensive (FHH)] with different StaH (DA = FHH > BN) were assigned to one of three treatment groups (n = 4/strain): nonoperated controls, surgically catheterized rats, or rats surgically catheterized and hemorrhaged 24 h postsurgery. Rats were euthanized 30 min after handling or 30 min after initiation of a 26 min hemorrhage. After euthanasia, hearts were removed and mitochondria isolated. Differential protein expression was determined using 2D DIGE-based Quantitative Intact Proteomics and proteins identified by MALDI/TOF mass spectrometry. Hundreds of proteins (791) differed among inbred rat strains (P ≤ 0.038), and of these 81 were identified. Thirty-eight were unique proteins and 43 were apparent isoforms. For DA rats (longest STaH), 36 proteins increased and 30 decreased compared with BN (shortest STaH). These 81 proteins were associated with lipid (e.g., acyl CoA dehydrogenase) and carbohydrate (e.g., fumarase) metabolism, oxidative phosphorylation (e.g., ubiquinol-cytochrome C reductase), ATP synthesis (F1 ATPase), and H2S synthesis (3-mercaptopyruvate sulfurtransferase). Although we cannot make associations between these identified mitochondrial proteins and StaH, our data do provide evidence for future candidate proteins with which to consider such associations.