Expression Levels Of Interferon-stimulated Genes Research Articles

HSV1-induced enhancement of productive HIV-1 replication is associated with interferon pathway downregulation in human macrophages.

Herpesviruses are common co-pathogens in individuals infected with human immunodeficiency virus (HIV). Herpes simplex virus type 1 (HSV1) enhances HIV-1 replication and has evolved mechanisms to evade or disrupt host innate immune responses, including interference with interferon (IFN) signalling pathways. The aimed of this work was evaluated whether it HSV1 affects HIV-1 replication through the modulation of the IFN pathway in human macrophages. Co-infections with HSV1 and HIV-1 were performed in monocyte-derived human macrophages (hMDMs). The production of infectious HIV-1 and HSV-1 was monitored 48 h post-coinfection. Additionally, mRNA and protein expression levels of interferon-stimulated genes (ISGs) were evaluated in both HIV-1-HSV1 coinfections and HSV1 mono-infections. The HSV1 coinfection increasing the HIV-1 productive replication, following of downregulation of interferon-alpha (IFN-α) and interferon-induced transmembrane protein 3 (IFITM3) expression in hMDMs. Acyclovir treatment, in a dose-dependent manner, mitigated HSV1's ability to decrease IFITM3 levels. Knockdown of HSV1 Us11 and virion host shutoff (VHS) genes reactivated the IFN pathway, evidenced by restored IFITM3 expression and activation of eIF2-α and PKR. This knockdown also returned HIV-1 replication to baseline levels. Our data suggested that HSV1 increases HIV-1 replication in human macrophages is associated with the downregulating interferon pathways and ISGs expression.

Type 1 Interferon-Stimulated Gene Expression and Disease Activity in Pediatric Rheumatic Diseases: No Composite Scores Needed?

Rheumatic diseases are characterized by different patterns of immune overactivation. This study investigated the correlation of whole blood type 1 interferon (IFN) stimulated gene (ISG), IL18, and CXCL9 expression with clinical disease activity in pediatric rheumatic diseases and assessed the required number of ISGs to be included in a composite type 1 IFN score. Whole blood-derived RNA and clinical data were collected from 171 mostly pediatric patients with connective tissue diseases (CTDs), systemic autoinflammatory diseases (SAIDs), monogenic interferonopathies (IFNPs) and other inflammatory diseases, and from 38 controls. The expression of six previously established ISGs, IL18, and CXCL9 was assessed by real-time polymerase chain reaction (471 samples). Individual and composite gene expression was assessed, and correlation and threshold analyses were performed. Correlation between ISG expression and clinical disease activity was strongest in CTD, especially in juvenile dermatomyositis (JDM) and IFNP, and modest in patients with SAID. Threshold ISG expression levels for the detection of at least mild clinical disease activity were substantially higher in patients with systemic lupus erythematosus compared with JDM. The correlation of expression levels of limited sets of ISGs and even individual ISGs with clinical disease activity were not inferior to a composite score of six ISGs. In a real-world cohort, individual ISG expression levels robustly reflected clinical disease activity in CTD and IFNP, especially in JDM, which would simplify such analyses in clinical routine and be more cost-effective. Threshold levels varied across diseases, potentially reflecting different mechanisms of type 1 IFN overactivation.

Multi-dimensional Insight into the Coexistence of Pathogenic Genes for ADAR1 and TSC2: Careful Consideration is Essential for Interpretation of ADAR1 Variants.

Aicardi-Goutières syndrome 6 (AGS6) is a serious auto-immunization-associated acute neurologic decompensation. AGS6 manifests as acute onset of severe generalized dystonia of limbs and developmental regression secondary to febrile illness mostly. Dyschromatosis symmetrica hereditaria (DSH), as pigmentary genodermatosis, is a characterized mixture of hyperpigmented and hypopigmented macules. Both AGS6 and DSH are associated with ADAR1 pathogenic variants. To explore the etiology of a proband with developmental regression with mixture of hyperpigmentation and hypopigmentation macules, we used the trio-WES. Later, to clarify the association between variants and diseases, we used guidelines of ACMG for variants interpretation and quantitative Real-time PCR for verifying elevated expression levels of interferon-stimulated genes, separately. By WES, we detected 2 variants in ADAR1 and a variant in TSC2, respectively, were NM_001111.5:c.1096_1097del, NM_001111.5:c.518A>G, and NM_000548.5:c.1864C>T. Variants interpretation suggested that these 3 variants were both pathogenic. Expression levels of interferon-stimulated genes also elevated as expected. We verified the co-occurrence of pathogenic variants of ADAR1 and TSC2 in AGS6 patients with DSH. Our works contributed to the elucidation of ADAR1 pathogenic mechanism, given the specific pathogenic mechanism of ADAR1, and it is necessary to consider with caution when variants were found in ADAR1.

Host Factor Nucleophosmin 1 (NPM1/B23) Exerts Antiviral Effects against Chikungunya Virus by Its Interaction with Viral Nonstructural Protein 3.

Chikungunya virus (CHIKV) hijacks host cell machinery to support its replication. Nucleophosmin 1 (NPM1/B23), a nucleolar phosphoprotein, is one of the host proteins known to restrict CHIKV infection; however, the mechanistic details of the antiviral role of NPM1 are not elucidated. It was seen in our experiments that the level of NPM1 expression affected the expression levels of interferon-stimulated genes (ISGs) that play antiviral roles in CHIKV infection, such as IRF1, IRF7, OAS3, and IFIT1, indicating that one of the antiviral mechanisms could be through modulation of interferon-mediated pathways. Our experiments also identified that for CHIKV restriction, NPM1 must move from the nucleus to the cytoplasm. A deletion of the nuclear export signal (NES), which confines NPM1 within the nucleus, abolishes its anti-CHIKV action. We observed that NPM1 binds CHIKV nonstructural protein 3 (nsP3) strongly via its macrodomain, thereby exerting a direct interaction with viral proteins to limit infection. Based on site-directed mutagenesis and coimmunoprecipitation studies, it was also observed that amino acid residues N24 and Y114 of the CHIKV nsP3 macrodomain, known to be involved in virus virulence, bind ADP-ribosylated NPM1 to inhibit infection. Overall, the results show a key role of NPM1 in CHIKV restriction and indicate it as a promising host target for developing antiviral strategies against CHIKV. IMPORTANCE Chikungunya, a recently reemerged mosquito-borne infection caused by a positive-sense, single-stranded RNA virus, has caused explosive epidemics in tropical regions. Unlike the classical symptoms of acute fever and debilitating arthralgia, incidences of neurological complications and mortality were reported. Currently there are no antivirals or commercial vaccines available against chikungunya. Like all viruses, CHIKV uses host cellular machinery for establishment of infection and successful replication. To counter this, the host cell activates several restriction factors and innate immune response mediators. Understanding these host-virus interactions helps to develop host-targeted antivirals against the disease. Here, we report the antiviral role of the multifunctional host protein NPM1 against CHIKV. The significant inhibitory effect of this protein against CHIKV involves its increased expression and movement from its natural location within the nucleus to the cytoplasm. There, it interacts with functional domains of key viral proteins. Our results support ongoing efforts toward development of host-directed antivirals against CHIKV and other alphaviruses.

Meloxicam inhibits STING phosphorylation and alleviates intracellular DNA-mediated autoimmune responses

BackgroundCyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is critical for cytosolic DNA-sensing and the subsequent immune responses. The inappropriate activation of this pathway leads to DNA-induced autoimmune response. Understanding the precise regulation of cGAS-STING pathway is important for developing therapeutics to treat several autoimmune diseases caused by self-DNA.ResultsWe report that Meloxicam (MXC) inhibits intracellular DNA-, but not RNA-induced immune responses. We find that MXC inhibits the phosphorylation of STING by examining in different cells with various DNA stimulations. We further find that MXC significantly dampens the expression levels of interferon-stimulated genes (ISGs) by using DNA 3’ repair exonuclease 1 (TREX1)-deficient cell, an experimental model for self-DNA-induced autoimmune disease. Importantly, we demonstrate that MXC could promote the survival in Trex1–/– mouse model for Aicardi-Goutières syndrome (AGS).ConclusionsOur study identified a non-steroidal anti-inflammatory drug, MXC, that exhibits potential effect in treating the autoimmunity caused by self-DNA.

Transcriptome profiling in swine macrophages infected with African swine fever virus at single-cell resolution

African swine fever virus (ASFV) is the causative agent of African swine fever, a highly contagious and usually fatal disease in pigs. The pathogenesis of ASFV infection has not been clearly elucidated. Here, we used single-cell RNA-sequencing technology to survey the transcriptomic landscape of ASFV-infected primary porcine alveolar macrophages. The temporal dynamic analysis of viral genes revealed increased expression of viral transmembrane genes. Molecular characteristics in the ASFV-exposed cells exhibited the activation of antiviral signaling pathways with increased expression levels of interferon-stimulated genes and inflammatory- and cytokine-related genes. By comparing infected cells with unexposed cells, we showed that the unfolded protein response (UPR) pathway was activated in low viral load cells, while the expression level of UPR-related genes in high viral load cells was less than that in unexposed cells. Cells infected with various viral loads showed signature transcriptomic changes at the median progression of infection. Within the infected cells, differential expression analysis and coregulated virus–host analysis both demonstrated that ASFV promoted metabolic pathways but inhibited interferon and UPR signaling, implying the regulation pathway of viral replication in host cells. Furthermore, our results revealed that the cell apoptosis pathway was activated upon ASFV infection. Mechanistically, the production of tumor necrosis factor alpha (TNF-α) induced by ASFV infection is necessary for cell apoptosis, highlighting the importance of TNF-α in ASFV pathogenesis. Collectively, the data provide insights into the comprehensive host responses and complex virus–host interactions during ASFV infection, which may instruct future research on antiviral strategies.

Regulation of interferon stimulated gene expression levels at homeostasis

Interferon stimulated genes (ISGs), a collection of genes important in the early innate immune response, are upregulated in response to stimulation by extracellular type I interferons. The regulation of ISGs has been extensively studied in cells exposed to significant interferon stimulation, but less is known about ISG regulation in homeostatic regimes in which extracellular interferon levels are low. Using a collection of pre-existing, publicly available microarray datasets, we investigated ISG regulation at homeostasis in CD4, pulmonary epithelial, fibroblast and macrophage cells. We used a linear regression model to predict ISG expression levels from regulator expression levels. Our results suggest significant regulation of ISG expression at homeostasis, both through the ISGF3 molecule and through IRF7 and IRF8 associated pathways. We find that roughly 50% of ISGs have expression levels significantly correlated with ISGF3 expression levels at homeostasis, supporting previous results suggesting that homeostatic IFN levels have broad functional consequences. We find that ISG expression levels varied in their correlation with ISGF3, with epithelial and macrophage cells showing more correlation than CD4 and fibroblast cells. Our analysis provides a novel approach for decomposing and quantifying ISG regulation.

Two types of poor immunological responder showing distinct responses to long-term HAART

ObjectivesMost previous studies on poor immunological responders (PIRs) have been performed on one cohort at one time-point following highly active antiretroviral therapy (HAART). The aim of this study was to investigate whether there are different subtypes of PIR and whether a certain population might achieve better immune reconstitution following longer HAART. MethodsThis study was designed as an ambispective cohort study, including a 4–5-year retrospective study and a 2-year prospective follow-up investigation. Thymic output, activated T cell and regulatory T cell (Treg) subset frequencies, expression levels of interferon-stimulated genes, and plasma concentrations of neopterin were determined at 4–5 years and 6–7 years following HAART initiation. ResultsPIRs were subdivided into two populations after 4–5 years of HAART, according to the kinetics of T cell recovery. Type II PIRs exhibited a significantly lower percentage of naïve CD4+ T cells and CD31+ naïve CD4+ T cells compared with type I PIRs. After an additional 2 years of HAART treatment, type I PIRs showed a better outcome than type II PIRs. Furthermore, it was found that 2 years of additional HAART could persistently improve thymic output. ConclusionsThe two PIR subgroups are different in terms of immune characteristics and the response to prolonged HAART.

Janus kinase 1/2 inhibition for the treatment of autoinflammation associated with heterozygous TNFAIP3 mutation

Janus kinase 1/2 inhibition for the treatment of autoinflammation associated with heterozygous TNFAIP3 mutation

Abstract 726: Type-I interferon and epigenetic modulators enhance the anti-tumor efficacy of a dendritic-cell targeting MIP3α-antigen vaccine in the B16F10 mouse model

Abstract Background: The chemokine MIP-3α (CCL20) binds to CCR6 found on immature dendritic cells. DNA vaccines fusing MIP-3α to melanoma-associated antigens have been shown to be effective in therapeutically reducing melanoma tumor burden in mouse models. However, the anti-tumor efficacy was not complete. To optimize the therapy, our laboratory has added agents designed to overcome immunoregulatory mechanisms of the tumor microenvironment. Here, we report that the combination of type-I interferon therapy (IFN) with 5-Aza-2'-deoxycitidine (Aza), which has been shown to prevent silencing of interferon responsive genes, profoundly enhanced the therapeutic anti-melanoma efficacy of a MIP-3α-antigen DNA vaccine. Methods: The current studies utilize the B16F10 syngeneic, transplantable, mouse melanoma model system. The MIP-3α-antigen DNA vaccine is administered intramuscularly (i.m.) into the tibialis muscle, followed immediately by i.m. electroporation. The primary construct utilized includes MIP-3α fused to immunogenic regions of gp100 and tyrosinase related protein 2 (TRP-2). Vaccinations are given thrice at one week intervals, beginning at day 5 post challenge. Two days post vaccination, CpG adjuvant is administered into the vaccinated muscle. Aza is given i.p.at 1mg/kg on the first two vaccination days. IFN therapy is given in a series of one high dose followed by three days of low doses, beginning on the first two vaccination days. Tumor sizes, growth, and survival were all assessed. Vaccine antigens and interferon stimulated gene expression levels were explored by RT-PCR. Results: With this therapeutic protocol, we demonstrate for the first time that the addition of IFN therapy with Aza enhances the anti-tumor efficacy of a MIP-3α-gp100-TRP2 vaccine. Combination therapy has led to significantly reduced tumor burden and overall increases in mouse survival, increasing median survival of vaccine alone by 39% and negative control by 86%. Importantly, this increase in efficacy was dependent on the presence of all three components, including vaccine, IFN, and Aza. All permutations of one or two treatments provided inferior efficacy to the triple therapy. The immunological details of this model are under current investigation. Conclusions: Efficient targeting of antigen to immature dendritic cells with a chemokine fusion vaccine offers a potential alternative approach to the ex vivo dendritic cell antigen loading protocols currently undergoing clinical investigation. Combining this approach with IFN therapy enhanced by Aza treatment significantly improved vaccine efficacy. Further potential therapy optimization currently undergoing investigation offers promise for this line of investigation to become a novel melanoma therapy. Citation Format: James Gordy, Richard Markham. Type-I interferon and epigenetic modulators enhance the anti-tumor efficacy of a dendritic-cell targeting MIP3α-antigen vaccine in the B16F10 mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 726.

Nonstructural 5A Protein of Hepatitis C Virus Interferes with Toll-Like Receptor Signaling and Suppresses the Interferon Response in Mouse Liver.

The hepatitis C virus nonstructural protein NS5A is involved in resistance to the host immune response, as well as the viral lifecycle such as replication and maturation. Here, we established transgenic mice expressing NS5A protein in the liver and examined innate immune responses against lipopolysaccharide (LPS) in vivo. Intrahepatic gene expression levels of cytokines such as interleukin-6, tumor necrosis factor-α, and interferon-γ were significantly suppressed after LPS injection in the transgenic mouse liver. Induction of the C-C motif chemokine ligand 2, 4, and 5 was also suppressed. Phosphorylation of the signal transducer and activator of transcription 3, which is activated by cytokines, was also reduced, and expression levels of interferon-stimulated genes, 2’-5’ oligoadenylate synthase, interferon-inducible double-stranded RNA-activated protein kinase, and myxovirus resistance 1 were similarly suppressed. Since LPS binds to toll-like receptor 4 and stimulates the downstream pathway leading to induction of these genes, we examined the extracellular signal-regulated kinase and IκB-α. The phosphorylation levels of these molecules were reduced in transgenic mouse liver, indicating that the pathway upstream of the molecules was disrupted by NS5A. Further analyses revealed that the interaction between interleukin-1 receptor-associated kinase-1 and tumor necrosis factor receptor associated factor-6 was dispersed in transgenic mice, suggesting that NS5A may interfere with this interaction via myeloid differentiation primary response gene 88, which was shown to interact with NS5A. Since the gut microbiota, a source of LPS, is known to be associated with pathological conditions in liver diseases, our results suggest the involvement of NS5A in the pathogenesis of HCV infected-liver via the suppression of innate immunity.

Characterization of CD4+ T cells expressing an elevated interferon-stimulated gene signature in SLE patients

Abstract The type I interferon (IFN) signaling pathway plays a key role in Systemic Lupus Erythematosus (SLE) pathology, and a majority of patients display elevated expression levels of interferon-stimulated genes (ISGs) in the peripheral blood. However, it is unclear which immune cells are responding to IFN to drive disease pathology. We compared the ISG signatures of cell types sorted from peripheral blood of IFNβ-treated relapsing-remitting multiple sclerosis (RRMS) patients with those of SLE patients. While systemic IFNβ treatment stimulated ISG expression in the monocytes and neutrophils of RRMS patients, the ISG signature in SLE patients was primarily detected in CD4+ T and B cells. This suggests these cells may be exposed to higher levels of IFN in microenvironments of inflammation within SLE patients, such as upon interaction with APC presenting SLE antigens. We hypothesize that a subset of primarily antigen-specific CD4+ T cells expand and express ISGs during SLE disease activity, and that these cells and their signature pathways can serve as disease biomarkers and therapeutic targets. To examine ISG expression by CD4+ T cells in SLE, we compared the expression of several ISG-correlated surface markers between high- and low-IFN score patients and healthy controls. Subsets of CD4+ T cells in high-IFN score patients expressed elevated levels of PD1, CD66a, and OX40, while the majority of cells expressed a similar level as cells in healthy controls. This suggests that only a small subset of CD4+ T cells is activated by localized IFN sources and is involved in SLE pathology. We have further characterized PD1+, OX40+ CD66a+, and SLE-specific memory CD4+ T cells by RNAseq and flow cytometry.

Interferon stimulated genes as peripheral diagnostic markers of early pregnancy in sheep: a critical assessment

We investigated the diagnostic reliability of pregnancy detection using changes in interferon stimulated gene (ISG) messenger RNA (mRNA) levels in circulating immune cells in ewes. Two different groups of ewes (an experimental group, experiment 1 and a farm group, experiment 2) were oestrus-synchronized and blood sampled on day 14 (D0=day of insemination in control animals, experiment 1) and day 15 (experiment 2). Real-time PCR were performed to evaluate the abundance of different ISG mRNAs. In the experimental group, peripheral blood mononuclear cells of 29 ewes born and bred in experimental facilities were isolated using a Percoll gradient method. Gene expression for Chemokine (C-X-C motif) ligand 10 (CXCL10), Myxovirus (influenza virus) resistance 1 (MX1) and Signal transducer and activator of transcription 1 (STAT1) mRNA were, respectively, 8.3-fold, 6.1-fold and 2.7-fold higher (P<0.001) in pregnant compared with non-pregnant ewes. The receiver operating characteristic (ROC) curves generated from the real-time PCR data demonstrated that a reliable cut-off could be established for CXCL10, MX1 and STAT1. In the farm group of animals, peripheral blood leucocytes of 37 cross-bred multiparous ewes bought from several herds were isolated using the PAXgene® procedure. This blood sampling procedure is achievable in farms, whereas the Percoll method is not. No significant differences (P>0.10) in CXCL10, STAT1, MX1, Myxovirus (influenza virus) resistance 2 (MX2) and ISG15 ubiquitin-like modifier (ISG15) mRNA expression were found between pregnant and non-pregnant ewes. The ROC curves and the hierarchical classification generated from the real-time PCR data failed to discriminate between pregnant and non-pregnant animals. In this group of animals, our results show a strong variability in ISG expression patterns: 17% of animals identified as non-pregnant by the five tests were in fact pregnant, only 52% of pregnant animals had at least two positive results (two genes above threshold), whereas up to five positive results (five genes above threshold) were needed to avoid misclassification. In conclusion, this study illustrates the high variability in ISG expression levels in immune circulating cells during early pregnancy and, therefore, highlights the limits of using ISG expression levels in blood samples, collected on PAXgene® tubes on farms, for early pregnancy detection in sheep.

P281 Prevalence of primary and secondary to therapy antiviral resistance by determination of HBV polymerase gene mutations in patients with CHB

Common genetic variation within the IL28 locus has been found to influence the effect of peg-interferon and ribavirin combination therapy against chronic hepatitis C virus (HCV) infection. Expression of IL28 in peripheral blood cells has been reported to be higher in patients with IL28 SNP genotypes associated with favorable response.We analyzed 52 liver and 114 blood samples obtained from patients with HCV genotype 1b. We used reverse transcription-real time polymerase chain reaction to analyze expression levels of IL28 and several interferon stimulated genes (ISGs), including MxA, double stranded RNA dependent protein kinase (PKR), 2′–5′ oligo-nucleotide synthetase (OAS1), ISG15, and SOCS1.Interestingly, expression of IL28 was significantly lower in patients with the response-favorable rs8099917 TT genotype compared to those with TG or GG genotypes (p <0.005). In hepatic cells, expression of MxA, PKR, OAS1, and ISG15 were also significantly lower in rs8099917 TT patients (p <0.001, p = 0.005, p = 0.001, p <0.001, respectively), whereas in peripheral blood mononuclear cells ISG expression levels did not differ significantly. Among patients treated with peg-interferon plus ribavirin therapy, liver mRNA levels of IL28, MxA, PKR, OAS1, and ISG15 were significantly or marginally lower in responders who became negative for HCV RNA (p = 0.001, 0.004, 0.014, 0.051, and 0.015, respectively).Expression levels of ISGs are differentially regulated in the liver and peripheral blood. The mechanism underlying the expression levels of IL28 and ISGs and the correlation with the effect of the therapy should be further investigated.

Impact of interleukin‐28B genotype on in vitro and in vivo systems of hepatitis C virus replication

Identification of the relationship between the interleukin (IL)-28B genotype and the effect of peginterferon plus ribavirin treatment has had a great impact on the study of antiviral therapy for patients with chronic hepatitis C virus (HCV) infection. Differential expression levels of interferon-stimulated genes (ISG) in the liver and white blood cells based on the IL-28B genotype, which may in turn lead to differences in outcome of therapy, indicate that previous studies should be re-evaluated taking the effect of the IL-28B single nucleotide polymorphism (SNP) into consideration, although the exact mechanism of how variation in IL-28B SNPs affect HCV eradication remains unknown. These results suggest that the genotypes of multiple cell types, including liver and immune cells, contribute to the efficacy of therapy. Studies using human hepatocyte chimeric mice, in which effector cells of the human adaptive immune response are absent, showed that viral load, ISG expression levels and reduction of HCV RNA by interferon are affected by the IL-28B genotype. Genetic differences among hepatocytes may, therefore, contribute to differences in baseline viral loads and response to interferon therapy. Further studies should be done to clarify the mechanism of action of IL-28B SNP on viral load and effect of interferon treatment. Advances in cell culture systems and human hepatocyte chimeric mice, as well as upcoming in vitro and in vivo experimental systems, provide an effective platform to examine the effects of host and viral genetic variation on infection and response to interferon.

IL28 variation affects expression of interferon stimulated genes and peg-interferon and ribavirin therapy

Common genetic variation within the IL28 locus has been found to influence the effect of peg-interferon and ribavirin combination therapy against chronic hepatitis C virus (HCV) infection. Expression of IL28 in peripheral blood cells has been reported to be higher in patients with IL28 SNP genotypes associated with favorable response. We analyzed 52 liver and 114 blood samples obtained from patients with HCV genotype 1b. We used reverse transcription-real time polymerase chain reaction to analyze expression levels of IL28 and several interferon stimulated genes (ISGs), including MxA, double stranded RNA dependent protein kinase (PKR), 2'-5' oligo-nucleotide synthetase (OAS1), ISG15, and SOCS1. Interestingly, expression of IL28 was significantly lower in patients with the response-favorable rs8099917 TT genotype compared to those with TG or GG genotypes (p<0.005). In hepatic cells, expression of MxA, PKR, OAS1, and ISG15 were also significantly lower in rs8099917 TT patients (p<0.001, p=0.005, p=0.001, p<0.001, respectively), whereas in peripheral blood mononuclear cells ISG expression levels did not differ significantly. Among patients treated with peg-interferon plus ribavirin therapy, liver mRNA levels of IL28, MxA, PKR, OAS1, and ISG15 were significantly or marginally lower in responders who became negative for HCV RNA (p=0.001, 0.004, 0.014, 0.051, and 0.015, respectively). Expression levels of ISGs are differentially regulated in the liver and peripheral blood. The mechanism underlying the expression levels of IL28 and ISGs and the correlation with the effect of the therapy should be further investigated.

Correlation of type I, -II and -III interferon expression in the liver with clinical and viral parameters in chronic HCV infection

Aims: It has been reported that expression of Interferon-stimulated genes (ISGs) in the liver of patients with chronic hepatitis C (HCV) correlates with sustained virological response (SVR) to antiviral treatment. It is not well understood by which IFNs these ISGs are induced or whether expression of IFNs is associated with virological parameters or therapy outcome. Methods: HCV load and IFNs (-α, -β, -γ, -λ [IL28a, IL28b, IL29], and IFN-ω) were determined in liver biopsies of 60 HCV patients prior to antiviral therapy and in 10 non-HCV patients by qt RT-PCR. Clinical parameters including HCV load in serum and liver transaminases were analyzed 36 hours, 4 weeks and 12 weeks after initiation of therapy. Results: IFN-α, IFN-β and -γ expression levels could be detected in biopsies of 55%, 73% or 88% of HCV patients, respectively. IFN-α expression was not correlated to clinical parameters like HCV load, genotype, transaminases, fibrosis staging, inflammation grading or expression of ISGs while expression of IFN-β was associated with lower expression levels of ISGs (p&lt;0.002). Higher expression levels of IFN-γ were found in patients with elevated liver transaminases (p&lt;0,003, ALT) and with higher stages of fibrosis (p&lt;0.007). No correlations were found between IFN-γ expression and inflammation grading, HCV serum load, genotype, antiviral response or ISG expression levels. IFN-λ and –ω expression was detectable in less than 10% of HCV positive liver biopsies. Conclusions: Prognostically relevant hepatic expression of ISGs in HCV patients is primarily correlated to the expression of type I and II IFNs while type III IFNs are only rarely detectable. Hepatocyte damage is associated with the presence of IFN-γ. None of the IFNs is correlated to the clinical and virological response to therapy which leads us to hypothesize that the unfavorable induction of ISGs may be due to „hyper-responsiveness“ of the target cells to IFNs rather than overproduction of IFNs.