Role of Interferons in Chronic Hepatitis C Infection.

It is known that the production of and/or response to interferon (IFN) are deregulated during chronic hepatitis C virus (HCV) infection. In particular, several studies have shown that patients with chronic HCV infection who have a high natural level of IFN-stimulated genes (ISGs) do not achieve viral clearance and have a poor response to treatment with pegylated IFNα and ribavirin. The viral and/or host factors that are responsible for the higher endogenous ISGs expression in some HCV infected patients compared to others remain to be determined. However, type III IFNs, and in particular the new discovered IFN lambda (L) 4 Gene, appear to play a dominant role in driving ISGs response and in contributing to the establishment of HCV persistence. This review focuses on recent studies on how the ISGs response and the IFNλ genetic factors (interleukin-28B and IFNL4) affect the clinical outcome of HCV infection highlighting their impact in the current antiviral therapies with direct acting antiviral agents.

Consolidation of molecular testing in clinical virology.

INTRODUCTION: The development of quantitative methods for the detection of viral nucleic acids have significantly improved our ability to manage disease progression and to assess the efficacy of antiviral treatment. Moreover, major advances in molecular technologies during the last decade have allowed the identification of new host genetic markers associated with antiviral drug response but have also strongly revolutionized the way we see and perform virus diagnostics in the coming years. Areas covered: In this review, we describe the history and development of virology diagnostic methods, dedicating particular emphasis on the gradual evolution and recent advances toward the introduction of multiparametric platforms for the syndromic diagnosis. In parallel, we outline the consolidation of viral genome quantification practice in different clinical settings. Expert commentary: More rapid, accurate and affordable molecular technology can be predictable with particular emphasis on emerging techniques (next generation sequencing, digital PCR, point of care testing and syndromic diagnosis) to simplify viral diagnosis in the next future.

IFN-stimulated gene expression is independent of the IFNL4 genotype in chronic HIV-1 infection.

This study aimed to evaluate the association between the IFNL4 rs368234815 (ΔG/TT) dinucleotide polymorphism and the IFN response during chronic HIV-1 infection. We carried out genotyping analysis and measured the expression of IFN-stimulated genes (ISGs) (myxovirus resistance protein A [MxA], ISG15, ISG56, apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like [APOBEC] 3F and APOBEC3G) on peripheral blood mononuclear cells collected from naïve and HAART-treated HIV-1-infected patients. There were no statistically significant differences in endogenous ISGs mRNA levels among HIV-1-positive patients bearing different IFNL4 genotypes, suggesting that ISG expression is independent of the IFNL4 genotype in HIV-1 infection.

ISG15 expression correlates with HIV-1 viral load and with factors regulating T cell response.

Given the multifactorial nature of action of type I interferon (IFN) in HIV-1 infection and the need to firmly establish the action of key components of IFN pathways, we compared the IFN stimulated gene (ISG)15 expression with that of other well-characterized ISGs, evaluating its relationship with immunosuppressive factors regulating T-cell response in HIV-1 patients. PBMC from 225 subjects were included: healthy donors (n=30), naïve (n=93) and HAART treated HIV-1 subjects (n=102). Levels of ISG15-mRNA, ISG56-mRNA, APOBEC3G/3F-mRNA, TRAIL-mRNA, IDO-mRNA, proviral load andISG15 (rs15842 and rs1921) SNPs were evaluated by using TaqMan assays. We found that ISG15, ISG56, APOBEC3G/3F levels were increased in untreated HIV-1 patients compared to healthy donors, being ISG15 the highest ISG expressed. The amount of ISG15 correlated with viral load and with CD4+ T cell counts whereas no relationship was found between all ISGs analyzed and proviral load or HIV-1 tropism. ISG15 expression was reduced following long-term antiretroviral therapy. In addition, ISG15 levels were correlated with those of TRAIL and IDO in HIV-1 viremic patients. Lastly, ISG15 SNPs had no influence on ISG15 levels. We demonstrates that ISG15 is elevated in viremic HIV-1 patients and is associated with high TRAIL and IDO levels.

MicroRNA-29 family expression and its relation to antiviral immune response and viro-immunological markers in HIV-1-infected patients.

BACKGROUND: Several in vitro studies suggested the microRNA-29 (miRNA-29) family is involved in regulating HIV-1 and modulating the expression of interleukin (IL)-32, an anti-HIV-1 cytokine. METHODS: To investigate the contribution of the miRNA-29 family to HIV-1 infection in vivo, we compared miRNA-29 expression in PBMC collected from 58 HIV-1-infected patients, naïve for antiretroviral therapy, and 21 gender- and age-matched HIV-1 seronegative healthy donors, using RT-Taqman assays. The relation between miRNA-29 levels and HIV-1 viro-immunological markers and the activation rate of antiviral immune response were also evaluated. In addition, we profiled miRNA-29 expression in CD4+ T lymphocytes and CD14+ monocytes collected from 5 antiretroviral treated HIV-1 infected patients. RESULTS: miRNA-29b levels were higher in HIV-1-infected patients than in the control group (p < 0.001). There were no correlations with either HIV-1 RNA levels or CD4+ T count, whereas a significant correlation was found between miRNA-29-a/c levels and integrated HIV-1 DNA (miRNA-29a: p = 0.009, r = -0.448; miRNA-29c: p = 0.029; r = -0.381). When the HIV-1-infected patients were grouped on the basis of their plasma HIV-1 RNA and CD4+ T cell count, we also found that patients expressing the lowest levels of miRNA-29c showed high viraemia, low CD4+ T cell count and high levels of integrated HIV-1 DNA. Moreover, miRNA-29b levels were correlated with those of IL-32nonα (p = 0.028; r = -0.298). Patients expressing higher levels of miRNA-29b showed lower levels of MxA, an interferon-stimulated gene, also induced by IL-32 (p = 0.006 r = -0.397). Lastly, we found that CD4+ T lymphocytes and CD14+ monocytes shared similar miRNA-29a/b/c expression patterns but the amount of miRNA-29a/b/c, IL-32 isoforms and MxA were highly variable in these two cellular subsets. CONCLUSIONS: The miRNA-29 family could influence the clinical progression of HIV-1 infection, the HIV-1 proviral load and the innate immune response against HIV-1.

Interleukin-32 isoforms: expression, interaction with interferon-regulated genes and clinical significance in chronically HIV-1-infected patients.

Given the growing evidence for a role of interleukin-32 (IL-32) in the immune response to HIV-1 infection and its interplay with type I and III interferons (IFNs), we studied the gene expression of IL-32 isoforms (α and nonα) in untreated chronically HIV-1-infected patients and in gender- and age-matched healthy individuals. To further characterize both the anti-HIV properties of IL-32 and the cytokine's relationship with host antiviral innate immune responses, we evaluated whether IL-32 can induce ex vivo the expression of antiviral IFN-induced genes (ISGs), namely myxovirus resistance A (MxA), and apolipoprotein B mRNA-editing enzyme catalytic (APOBEC)3G and APOBEC3F. We also investigated whether in vivo IL-32 (α and nonα) mRNA levels were correlated with those of MxA and APOBEC3G/3F. Results indicated that IL-32 (α and nonα) mRNA levels were significantly higher in HIV-1-infected patients than in healthy individuals. Furthermore, IL-32 (α and nonα) mRNA levels correlated negatively with HIV RNA levels, but not with the CD4(+) T-cell count. Our ex vivo studies disclosed that ISGs mRNA levels were increased after IL-32γ treatment of peripheral blood mononuclear cells. Interestingly, significant positive correlations were found between transcript levels of both IL-32α and IL-32nonα and those of MxA and APOBEC3G/3F in untreated chronically HIV-1-infected patients. Overall, our results demonstrated that IL-32 isoforms are highly expressed during chronic HIV-1 infection and that IL-32 could have a central role in the antiviral immune response against HIV-1.

Evaluation of viral load in infants hospitalized with bronchiolitis caused by respiratory syncytial virus.

The relationship between viral load, disease severity and antiviral immune activation in infants suffering from respiratory syncytial virus (RSV)-associated bronchiolitis has not been well identified. The main objective of this study was to determine the existence of a correlation between RSV load and disease severity and also between different clinical markers and mRNA levels of the interferon stimulated gene (ISG)56 in infants hospitalized for bronchiolitis. We also evaluated whether viral load tended to be persistent over the course of the RSV infection. The levels of RSV-RNA were quantified in nasopharyngeal washings, collected from 132 infants infected with RSV as a single (90.15%) or as a dual infection with other respiratory viruses (9.85%). Results indicated that viral load was positively related to the clinical severity of bronchiolitis, the length of hospital stay, the levels of glycemia and the relative gene expression of ISG56, whereas an inverse correlation was observed with the levels of hemoglobin. We also found that the RSV load significantly decreased between the first and second nasopharingeal washings sample in most subjects. These results suggest that infants with high RSV load on hospital admission are more likely to have both more severe bronchiolitis and a higher airway activation of antiviral immune response.

Evaluation of interleukin 28B single nucleotide polymorphisms in infants suffering from bronchiolitis.

The genetic diversity of the host is believed to be the key of the diversity in the clinical presentation of bronchiolitis. The aim of this study was to determine whether the known rs12979860 and rs8099917 single nucleotide polymorphisms (SNPs) in interleukin (IL)28B region, influence clinical features and natural history of bronchiolitis. Both SNPs showed no significant association with the risk of hospitalization for respiratory syncytial virus (RSV), viral load, disease severity, and other clinical features of patients. Interestingly infants carrying IL28B rs12979860 TT genotype had lower age at hospital admission than that of infants carrying CC/CT genotypes. Overall our results indicate that both IL28B SNPs had no impact on the clinical course of bronchiolitis with the only exception of the IL28B rs12979860 SNP which increased the risk of hospitalization for bronchiolitis at early age.

In vitro sensitivity of human metapneumovirus to type I interferons.

Human metapneumovirus (hMPV) has been recognized as an important respiratory pathogen. Due to its relatively recent discovery, only limited information is available on the relationship between hMPV and type I interferons (IFN). This study was designed to determine whether in vitro hMPV is sensitive to the antiviral activity of IFN-ß, leukocyte IFN-α, and several IFN-α subtypes in a human Hep-2 cell line. The results showed that 50% inhibitory concentration values against hMPV for the various type I IFN preparations were significantly higher than those against the IFN-sensitive vesicular stomatitis virus, and some IFN-α subtypes appeared to be more active against hMPV than others, with IFN-α subtypes 5, 6, 8, and 10 being the most potent, and IFN-α2, 17, and 21 the least potent. The results show that hMPV grown in Hep-2 is partially resistant to the antiviral activity of type I IFNs. Additional studies are required to understand whether and to what extent the relatively low sensitivity of hMPV to IFNs influences the clinical outcomes of infected individuals.

Pandemic 2009 H1N1 influenza virus is resistant to the antiviral activity of several interferon alpha subtypes.

Interferons (IFNs) are critically important in the control of influenza A virus infections. To better understand the pathogenic characteristics of the pandemic 2009 H1N1 influenza virus (pH1N1) from an innate immunity viewpoint, we investigated whether in vitro pH1N1 is sensitive to the antiviral activity of IFN beta, leukocyte IFN alpha, and several IFN alpha subtypes in a human lung adenocarcinoma epithelial cell line under single-growth cycle conditions. The results showed that 50% inhibitory concentration values against pH1N1 for various type I IFN preparations were higher than those against the IFN-sensitive encephalomyocarditis virus. Leukocyte IFN alpha and IFN alpha 5, 7, 8, 10, 14, 17, and 21 subtypes also appeared to be less active against pH1N1 than the Puerto Rico/8/34 H1N1 human influenza strain A. Taken together, the results provide new insights into the contributions of the various IFN alpha subtypes toward the regulation of innate immunity against pH1N1.