Interferon-lambda serum levels in hepatitis C

Effect of immunogenetics polymorphism and expression on direct-acting antiviral drug response in chronic hepatitis C

The prevalence of HCV infection in Egypt has decreased following the introduction of direct-acting antiviral therapy. However, treatment response is influenced by various factors, particularly host immunogenetics such as IL-28B and FOXP3 polymorphisms. The current study examined the impact of SNPs in the FOXP3 gene promoter region on HCV-infected Egyptian patients, along with SNPs in the IL28B gene.This study involved 99 HCV patients who achieved SVR12 after a 12 week DAA treatment while 63 HCV patients experienced treatment failure. IL28B rs12979860 SNP was identified using real-time PCR, while IL28B rs8099917, FOXP3 rs3761548, and rs2232365 SNPs were analyzed using RFLP-PCR. Serum levels of IL28B and FOXP3 were quantified using ELISA technique in representative samples from both groups. The IL28B rs12979860 T > C (P = 0.013) and FOXP3 rs2232365 A > G polymorphisms (P = 0.008) were found to significantly increase the risk of non-response. Responders had higher IL28B serum levels (P = 0.046) and lower FOXP3 levels (P < 0.001) compared to non-responders. Regression analysis showed an association between IL28B rs12979860 and FOXP3 rs2232365 with treatment response, independent of age and gender. A predictive model was developed with 76.2% sensitivity and 91.9% specificity for estimating DAAs response in HCV patients.Our findings confirmed the IL28B rs12979860 T > C and FOXP3 rs2232365 A > G polymorphisms significantly affect DAA treatment response in HCV Egyptian patients. Lower levels of IL-28B along with higher levels of FOXP3 are linked to poor response. Our results may lead to new insights into DAA responsiveness contributing to personalized medicine and improving therapeutic decision-making for HCV patients.

Biomarkers in Detection of Hepatitis C Virus Infection

The hepatitis C virus (HCV) infection affects 58 million people worldwide. In the United States, the incidence rate of acute hepatitis C has doubled since 2014; during 2021, this increased to 5% from 2020. Acute hepatitis C is defined by any symptom of acute viral hepatitis plus either jaundice or elevated serum alanine aminotransferase (ALT) activity with the detection of HCV RNA, the anti-HCV antibody, or hepatitis C virus antigen(s). However, most patients with acute infection are asymptomatic. In addition, ALT activity and HCV RNA levels can fluctuate, and a delayed detection of the anti-HCV antibody can occur among some immunocompromised persons with HCV infection. The detection of specific biomarkers can be of great value in the early detection of HCV infection at an asymptomatic stage. The high rate of HCV replication (which is approximately 1010 to 1012 virions per day) and the lack of proofreading by the viral RNA polymerase leads to enormous genetic diversity, creating a major challenge for the host immune response. This broad genetic diversity contributes to the likelihood of developing chronic infection, thus leading to the development of cirrhosis and liver cancer. Direct-acting antiviral (DAA) therapies for HCV infection are highly effective with a cure rate of up to 99%. At the same time, many patients with HCV infection are unaware of their infection status because of the mostly asymptomatic nature of hepatitis C, so they remain undiagnosed until the liver damage has advanced. Molecular mechanisms induced by HCV have been intensely investigated to find biomarkers for diagnosing the acute and chronic phases of the infection. However, there are no clinically verified biomarkers for patients with hepatitis C. In this review, we discuss the biomarkers that can differentiate acute from chronic hepatitis C, and we summarize the current state of the literature on the useful biomarkers that are detectable during acute and chronic HCV infection, liver fibrosis/cirrhosis, and hepatocellular carcinoma (HCC).

Interferon-λ3 rs12979860 can regulate inflammatory cytokines production in pulmonary fibrosis

Pulmonary fibrosis (PF) is the last phase of interstitial lung diseases (ILDs), which are a collection of pulmonary illnesses marked by parenchymal remodeling and scarring. Treatment can only halt the functional decline of the lung, raising the necessity of identifying the basic processes implicated in lung fibrogenesis. The Interferon lambda-3 (IFNL3) gene variant, rs12979860, was determined to be related to an elevated risk of fibrosis in different organs, but the mechanism through which it mediates fibrogenesis is not clear. In the current research, we aim to figure out some of the mechanistic pathways by which IFN-λ3 mediates ILDs. 100 healthy controls and 74 ILD patients were genotyped for IFNL3 rs12979860. Then the mRNA expression of IFNL3 and some other proinflammatory mediators was examined according to genotype in the peripheral blood mononuclear cells (PBMCs) of ILDs patients. The IFNL3 rs12979860 genotype distribution of healthy individuals and ILDs patients was shown to be in Hardy-Weinberg equilibrium (HWE) with a minor allele frequency (MAF) of 0.293 and 0.326, respectively. Furthermore, the CC genotype was demonstrated to be linked to enhanced IFNL3 expression. Also, the CC genotype was linked to an increase in the mRNA expression of TLR4 (P = 0.03) and the inflammatory cytokines IL-1β and TNF-α (P = 0.01 and 0.04, respectively) and had no effect on the NF-kB level (P = 0.3). From these results, we can deduce that IFN-λ3 may mediate tissue fibrosis via increasing the expression of IFN-λ3 itself and other proinflammatory mediators. This stimulates a self-sustaining loop mechanism which includes a reciprocal production of IFN-λ3, TLR4, IL-1β, and TNF-α leading to persistent inflammation and fibrosis.

HCV treatment outcome depends on SNPs of IFNL3-Gene polymorphisms (rs12979860) and cirrhotic changes in liver parenchyma

The allelic discrimination of IFNL3-(rs12979860 C > T) polymorphism reveals ambiguous associations with the effectiveness of oral HCV treatment. Solitary intra peripheral-blood-mononuclear-cells (PBMCs) HCV-RNA antisense-strands are independently detected in naïve and experienced cases regardless of viremia or hepatic-parenchymal alterations. We examined the frequencies of IFNL3-genetic variants with chronic-HCV-induced liver changes during the sustained virologic response (SVR) by evaluating the PBMCs- HCV-PCR after oral antiviral therapy. Methods: Twelve weeks after finishing oral antiviral therapy, the effects of IFNL3-genetic variants were evaluated in three groups of patients: Group-I (n = 25) showed HCV-RNA negativity in both serum and PBMCs-, group II (n = 52) showed positivity of HCV-RNA in PBMCs, and group-III (n = 25) had positive HCV-RNA in serum. The genetic variants of the IFNL3-gene were estimated for all the enrolled cases and correlated with their hepatic image changes. Results: IFNL3-(rs12979860) genotyping in post-direct acting antivirals (DAAs) SVR and HCV-relapse revealed: a) high frequency of CC-genotype and C-allele in group I compared to group II (P < 0.005) and group III(P ≤ 0.05) when hepatic-parenchyma looks normal by ultrasound b) frequent CT-genotype and T-allele in group II compared with I(P < 0.01) and III(P < 0.05) when liver tissues are bright (early cirrhotic-changes) c) frequent TT-genotype and T-allele in group III relative to I (P < 0.05) and II (P ≤ 0.08) when liver-tissues appear coarse by ultrasound. Conclusion: Outcomes of HCV treatment depend on host IFNL3-gene polymorphism and hepatic-parenchymal changes. A high frequency of wild-CC-genotype and C-allele is observed in patients with normal hepatic parenchyma and that achieved SVR. Solitary relapse in PBMCs occurs on increasing CT-genotype frequency when liver tissues are bright. Serologic relapse is detected when TT-genotype and T-allele are dominant in association with the cirrhotic liver. Therefore, IFNL3-gene-SNP analysis as a genetic predictor in relation to ultra-sonographic hepatic-parenchymal changes could be valuable for selecting the patients with the highest priority for treatment.

SNPs of the IFNL favour spontaneous clearance of HCV infection in children

BACKGROUND

Both spontaneous and treatment-induced clearance of hepatitis C virus (HCV) in adults have been associated with genetic polymorphisms in the interferon-λ genes. The aim of the present study was to confirm the association between the rs12979860 and evaluate the association between the rs368234815 and the rs4803217 single-nucleotide polymorphisms (SNPs) of the interferon-λ genes and the outcome of the infection in children.

METHODS

Alleles and genotypes frequencies of 32 children, who presented spontaneous clearance of the virus and 135 children, with viral persistence were compared with ethnically matched controls obtained from the 1000 Genomes Project and the International HapMap Project databases.

RESULTS

The frequencies of the C/C genotype of rs12979860, the TT/TT of the rs368234815 and the A/C of the rs4803217 were higher in the clearance group than in children with viral persistence (C/C versus T/T + C/T odds ratio (OR): 2.6; 90% confidence intervals (CI): 1.3-5; p = 0.01; TT/TT versus ΔG/TT + ΔG/ΔG OR: 2.8; 90% CI: 1.4-5.5; p = 0.01; and A/A versus A/C OR: 8.3; 90% CI: 1.5-45.9; p = 0.017, respectively) and with the ethnically matched controls.

CONCLUSIONS

The rs12979860, the rs368234815 and the rs4803217 SNPs are associated with spontaneous clearance of HCV in children.

IMPACT

Innate immune system response has a key role in the outcome of vertically acquired HCV infection in children. The rs12979860, the rs368234815 and the rs4803217 SNPs are associated with spontaneous clearance of HCV in children. Interferons-λ activate the Janus kinase-Stat pathway, which in turn induces several interferon-stimulated genes, leading to suppression of HCV replication both in vivo and in vitro.

Estimating the transmissibility of hepatitis C: A modelling study in Yichang City, China

Yichang is a city in central China in the Hubei Province. This study aimed to estimate the dynamics of the transmissibility of hepatitis C using a mathematical model and predict the transmissibility of hepatitis C in 2030. Data of hepatitis C cases from 13 counties or districts (cities) in Yichang from 2008 to 2016 were collected. A susceptible-infectious-chronic-recovered (SICR) model was developed to fit the data. The transmissibility of hepatitis C at the counties or districts was calculated based on new infections (including infected or chronically infected cases) reported monthly in the city caused by one infectious individual (MNI). The trend of the MNI was fitted and predicted using 11 models, with the coefficient of determination (R² ) was being used to test the goodness of fit of these models. A total of 3065 cases of hepatitis C were reported in Yichang from 2008 to 2016. The median MNI of Yichang was 0.0768. According to the fitting results and analysis, the trend of transmissibility of hepatitis C in Yichang City conforms with the logarithmic (R²  = 0.918, p < 0.001):MNI = 0.265-0.108 log(t) and exponential (R²  = 0.939, p < 0.001): MNI = 0.344e^(-0.278t) models. Hence, the transmission of hepatitis C virus at the county level has a downward trend. In conclusion, the transmissibility of hepatitis C in Yichang has a downward trend. With the current preventive and control measures in place, the spread of hepatitis C can be controlled.

IFN-λ1 Displays Various Levels of Antiviral Activity In Vitro in a Select Panel of RNA Viruses

Type III interferons (lambda IFNs) are a quite new, small family of three closely related cytokines with interferon-like activity. Attention to IFN-λ is mainly focused on direct antiviral activity in which, as with IFN-α, viral genome replication is inhibited without the participation of immune system cells. The heterodimeric receptor for lambda interferons is exposed mainly on epithelial cells, which limits its possible action on other cells, thus reducing the likelihood of developing undesirable side effects compared to type I IFN. In this study, we examined the antiviral potential of exogenous human IFN-λ1 in cellular models of viral infection. To study the protective effects of IFN-λ1, three administration schemes were used: 'preventive' (pretreatment); 'preventive/therapeutic' (pre/post); and 'therapeutic' (post). Three IFN-λ1 concentrations (from 10 to 500 ng/mL) were used. We have shown that human IFN-λ1 restricts SARS-CoV-2 replication in Vero cells with all three treatment schemes. In addition, we have shown a decrease in the viral loads of CHIKV and IVA with the 'preventive' and 'preventive/therapeutic' regimes. No significant antiviral effect of IFN-λ1 against AdV was detected. Our study highlights the potential for using IFN-λ as a broad-spectrum therapeutic agent against respiratory RNA viruses.

Host immune response in chronic hepatitis C infection: involvement of cytokines and inflammasomes

Chronic liver disease is a major health issue worldwide and chronic hepatitis C (CHC) is associated with an increased risk of cirrhosis and hepatocellular carcinoma (HCC). There is evidence that the hepatitis C virus (HCV) infection is correlated with immune senescence by way of immune activation and chronic inflammation, which lead to increased metabolic and cardiovascular risk, as well as progressive liver damage. Both the innate and adaptive immunity are firmly tied to the prognosis of an infection with HCV and its response to antiviral therapy. HCV is therefore associated with increased pro-inflammatory status, heightened production of cytokines, prolonged systemic inflammation, as well as increased morbidity and mortality, mainly due to the progression of hepatic fibrosis and HCC, but also secondary to cardiovascular diseases. Viral hepatic pathology is increasingly considered a disease that is no longer merely limited to the liver, but one with multiple metabolic consequences. Numerous in vitro studies, using experimental models of acute or chronic inflammation of the liver, has brought new information on immunopathological mechanisms resulting from viral infections and have highlighted the importance of involving complex structures, inflammasomes complex, in these mechanisms, in addition to the involvement of numerous proinflammatory cytokines. Beyond obtaining a sustained viral response and halting the aforementioned hepatic fibrosis, the current therapeutic “treat-to-target” strategies are presently focused on immune-mediated and metabolic disorders, to improve the quality of life and long-term prognosis of CHC patients.

Functional genetic variants of the IFN-λ3 (IL28B) gene and transcription factor interactions on its promoter

Interferon lambda 3 (IFN-λ3 or IFNL3, formerly IL28B), a type III interferon, modulates immune responses during infection/inflammation. Several human studies have reported an association of single nucleotide polymorphisms (SNP) in the IFNL3 locus with expression level of IFNL3. Previous genetic studies, in the context of hepatitis C virus infections, had predicted three regulatory SNPs: rs4803219, rs28416813 and rs4803217 that could have functional/causal roles. Subsequent studies confirmed this prediction for rs28416813 and rs4803217. A dinucleotide TA-repeat variant (rs72258881) has also been reported to be regulating the IFN-λ3 promoter. In this study, we tested all these genetic variants using a sensitive reporter assay. We show that the minor/ancestral alleles of both rs28416813 and rs4803217, together have a strong inhibitory effect on reporter gene expression. We also show an interaction between the two principal transcription factors regulating IFNL3 promoter: IRF7 and NF-kB RelA/p65. We show that IRF7 and p65 physically interact with each other. By using a transient ChIP assay, we show that presence of p65 increases the promoter occupancy of IRF7, thereby leading to synergistic activation of the IFNL3 promoter. We reason that, in contrast to p65, a unique nature of IRF7 binding to its specific DNA sequence makes it more sensitive to changes in DNA phasing. As a result, we see that IRF7, but not p65-mediated transcriptional activity is affected by the phase changes introduced by the TA-repeat polymorphism. Overall, we see that three genetic variants: rs28416813, rs4803217 and rs72258881 could have functional roles in controlling IFNL3 gene expression.

IFNL4 rs12979860 polymorphism influences HBV DNA viral loads but not the outcome of HBV infection in Moroccan patients

OBJECTIVES

The interferon (IFN) is known to bridge innate and adaptive immune responses, and to play a critical role particularly against hepatitis B virus (HBV) infection. Defects in IFN signals may result, therefore, in attenuated responses against HBV. Accordingly, polymorphisms in genes coding for immune response effectors may affect the clinical outcome of HBV infection. We analyzed the putative association between IFNL4 rs12979860 polymorphism and the outcome of HBV infection in Moroccan patients.

METHODS

In this study, 237 chronic HBV (CHB) patients and 129 spontaneously resolved HBV (SRB) individuals were enrolled and genotyped using a predesigned Taqman allelic discrimination assay.

RESULTS

Our data show a significant increase of HBV DNA loads in patients with IFNL4 rs12979860 CC genotype compared to patients with CT and TT genotypes (p = 0.0008). However, there was no consistent association between IFNL4 rs12979860 polymorphism and the outcome of HBV infection.

CONCLUSIONS

Although IFNL4 rs12979860 polymorphism seems to modulate circulating HBV DNA levels, it is disconnected from chronic disease progression. This observation suggests that the role of rs12979860 in liver disease is restricted to viral control and inactive in the deleterious immune pathology that affects liver tissue. Taken together, our data suggest that rs12979860 CC genotypes could be useful as a predictor of success or failure of IFN-based therapy in chronic HBV-infected patients.

Herpesviruses and the Type III Interferon System

Type III interferons (IFNs) represent the most recently discovered group of IFNs. Together with type I IFNs (e.g. IFN-α/β), type III IFNs (IFN-λ) are produced as part of the innate immune response to virus infection, and elicit an anti-viral state by inducing expression of interferon stimulated genes (ISGs). It was initially thought that type I IFNs and type III IFNs perform largely redundant functions. However, it has become evident that type III IFNs particularly play a major role in antiviral protection of mucosal epithelial barriers, thereby serving an important role in the first-line defense against virus infection and invasion at contact areas with the outside world, versus the generally more broad, potent and systemic antiviral effects of type I IFNs. Herpesviruseses are large DNA viruses, which enter their host via mucosal surfaces and establish lifelong, latent infections. Despite the importance of mucosal epithelial cells in the pathogenesis of herpesviruses, our current knowledge on the interaction of herpesviruses with type III IFN is limited and largely restricted to studies on the alphaherpesvirus herpes simplex virus (HSV). This review summarizes the current understanding about the role of IFN-λ in the immune response against herpesvirus infections.

The Key Roles of Interferon Lambda in Human Molecular Defense against Respiratory Viral Infections

Interferons (IFN) are crucial for the innate immune response. Slightly more than two decades ago, a new type of IFN was discovered: the lambda IFN (type III IFN). Like other IFN, the type III IFN display antiviral activity against a wide variety of infections, they induce expression of antiviral, interferon-stimulated genes (MX1, OAS, IFITM1), and they have immuno-modulatory activities that shape adaptive immune responses. Unlike other IFN, the type III IFN signal through distinct receptors is limited to a few cell types, primarily mucosal epithelial cells. As a consequence of their greater and more durable production in nasal and respiratory tissues, they can determine the outcome of respiratory infections. This review is focused on the role of IFN-λ in the pathogenesis of respiratory viral infections, with influenza as a prime example. The influenza virus is a major public health problem, causing up to half a million lethal infections annually. Moreover, the virus has been the cause of four pandemics over the last century. Although IFN-λ are increasingly being tested in antiviral therapy, they can have a negative influence on epithelial tissue recovery and increase the risk of secondary bacterial infections. Therefore, IFN-λ expression deserves increased scrutiny as a key factor in the host immune response to infection.

High-risk Allele for Herpes Labialis Severity at the IFNL3/4 Locus is Associated With Vestibular Neuritis

Objective: Vestibular neuritis (VN) is a peripheral vestibular disorder leading to a sudden loss of unilateral vestibular function. Although the underlying etiological mechanisms for disease development are not yet known, there is evidence that a latent infection with herpes simplex virus type 1 (HSV-1) might be involved. The polymorphism rs12979860 has been associated with the severity of recurrent herpes labialis and hepatitis C virus (HCV) clearance and treatment outcome and is located within the first intron of the IFNL4 gene on chromosome 19.q13.2. This case control study was conducted to evaluate the association of rs12979860 with VN occurrence.

Methods: DNA was extracted from EDTA blood of 151 VN patients and 1,775 healthy controls. Genotyping of rs12979860 was performed using iPLEX and MassARRAY Matrix Assisted Laser Desorption Ionization—Time of Flight (MALDI-TOF) mass spectrometry. For association analyses, an additive, dominant and recessive logistic regression model was calculated, using age and sex as covariates.

Results: A significant association of rs12979860 with VN was obtained for the additive [OR = 1.51 (1.18–1.92); p = 9.23 × 10⁻⁴] and dominant models [OR = 2.15 (1.48–3.13); p = 5.86 × 10⁻⁵], with the T allele being more frequent in the VN group.

Conclusion: By detecting a significant association of the rs12979860-T risk allele for herpes labialis severity with susceptibility to VN, this study gives further indirect evidence for an involvement of HSV-1 in VN pathology, thereby strengthening the virus hypothesis.

Association between interferon lambda 3 rs12979860 polymorphism and clinical outcome in dengue virus-infected children

Single nucleotide polymorphisms (SNPs) in immune-related genes have been shown to play a role in driving the development of the severe phenotypes of dengue virus (DENV) infection. We assessed the association between IFNL3 gene SNP (rs12979860) and dengue clinical outcomes in children. Patients with dengue-related symptoms (aged 1-15 years) admitted at a public hospital in Northeast Brazil were invited to participate. The association between rs12979860 polymorphism and dengue classification and clinical signs and symptoms were analysed. A total of 206 DENV-infected children were included: 53.4% of the infections were classified as severe dengue. The T allele carriers had higher risk of developing severe dengue when compared to CC genotype carriers (OR: 1.81; 95% CI: 0.98-3.32 p = .054). The T allele carriers also showed longer fever episodes when compared to patients with the CC genotype (OR: 1.90; 95%CI: 1.07-3.38; p = .027). On the other hand, the ones carrying the CT/TT genotype had 70% lower chance of developing thrombocytopenia when compared to those with the CC genotype (OR: 0.30; 95%CI: 0.08-0.88; p = .042). Our findings demonstrated that the T allele carriers of the IFNL3 gene had higher risk of developing severe dengue, suggesting a link between IFN-λ expression and DENV immunopathogenesis.

The presence of IFL3/4 rs12979860 C allele influences the in vitro IP-10 production by mononuclear cells from patients with systemic lupus erythematosus

OBJECTIVE

To explore whether the IFNL3/4 rs12979860 genotype may influence serum levels or production of interferon-inducible protein-10 (IP-10) by peripheral blood mononuclear cells from patients with systemic lupus erythematosus (SLE).

METHODS

Sixty-six patients with SLE and 22 healthy blood donors (controls) were included. The IFNL3/4 rs12979860 polymorphism was genotyped by real-time polymerase chain reaction. IP-10 levels in sera supernatants of IFNα stimulated peripheral blood mononuclear cells were measured by enzime-linked immunosorbent assay.

RESULTS

Allelic frequencies were CC (29%), CT (52%) and TT (20%) in SLE, and CC (32%), CT (41%) and TT (27%) in healthy controls. Median serum IP-10 levels were higher in SLE patients than in controls (190.8 versus 118.1 pg/ml; p < 0.001), particularly in those with high disease activity (278.5 versus 177.2 pg/ml; p = 0.037). However, serum IP-10 levels were not influenced by IFNL3/4 genotypes. Higher IP-10 production by peripheral blood mononuclear cells was found in both SLE patients (median 519.3 versus 207.6 pg/ml; p = 0.012) and controls (median 454.0 versus 201.7 pg/ml; p = 0.034) carrying the IFNL3/4 C allele compared with carriers of the T allele.

CONCLUSIONS

Although IFNL3/4 rs12979860 allele C does not appear to influence serum IP-10 levels in SLE, it plays an important role in the production of IP-10 by peripheral blood mononuclear cells after IFNα stimulation.

Correlation between female sex, IL28B genotype, and the clinical severity of bronchiolitis in pediatric patients

BACKGROUND

Single-nucleotide polymorphisms (SNPs) that impact on the differential expression of interleukin 28B (IL28B) are implicated in the progression of viral-induced diseases. In this prospective longitudinal cohort study, we evaluated the association between IL28B SNPs rs12979860 and rs8099917 and the clinical outcome of bronchiolitis in pediatric patients.

METHODS

A total of 682 infants suffering from bronchiolitis, categorized based on the final clinical outcome as mild or severe, were genotyped for IL28B SNPs rs12979860 and rs8099917.

RESULTS

When infants were categorized exclusively based on the final clinical outcome, no association was established between IL28B SNPs and the severity of bronchiolitis. However, when stratified by sex, the homozygotes for the minor alleles of rs12979860 (T) and rs8099917 (G) were associated with a mild disease in girls but not in boys.

CONCLUSION

SNPs rs12979860 and rs8099917 correlate with the severity of bronchiolitis and display a sex bias, where GG rs8099917 and TT rs12979860 genotypes are associated with a mild disease in girls but not in boys. These findings suggest that innate immunity and female sex links with the outcome of the diseases induced by respiratory viruses, such as RSV.

IL28B Genetic Variations in Patients with Recurrent Herpes Simplex Keratitis

Background and objectives: Recurrent herpes simplex keratitis (HSK) is the most common cause of corneal blindness in the developed world. A relationship between host gene polymorphisms and the recurrence of herpes simplex virus (HSV) infection has previously been proposed. Thus, the aim of this study was to investigate a potential association between the IL28B host genotype and recurrent HSK. Materials and Methods: Eighty patients older than 18 years of age of both genders with a history of recurrent herpes simplex labialis (HSL) were considered for inclusion. Seventy-five of these patients were found to be seropositive for HSV-1 and were subsequently enrolled in the study. Twenty-four of the enrolled patients also had a history of recurrent HSK associated with severe corneal scarring and visual acuity deterioration. Total DNA was isolated from whole blood samples. A single-nucleotide polymorphism (SNP) rs12979860 near the IL28B gene on chromosome 19 was genotyped. Results: A significant association was observed between recurrent HSK and two SNPs of the IL28B genotype (CCrs12979860 and CTrs12979860, p < 0.01). The variation CCrs12979860 showed a significantly greater association with HSK (16 out of 26 patients) compared with CTrs12979860 (8 out of 34 patients). Conclusion: Seropositive individuals with a history of recurrent HSK are likely to have the CC IL28B genotype. This genotype may be related to incomplete control of the infection and more frequent periodical viral shedding along the first nerve branch of the trigeminal ganglion, which clinically manifests as recurrent herpes keratitis. The clinical manifestation of recurrent HSV-1 infection seems to be influenced by polymorphism of the IL28B genotype.

Correlation between interleukin-28 gene polymorphism with interleukin-28 cytokine levels and viral genotypes among HCV patients in Yazd, Iran

OBJECTIVES

Recent studies using genome-wide association studies (GWAS) have shown the strong association between polymorphisms near the interleukin-28B (IL-28B) gene and spontaneous clearance of hepatitis C virus (HCV). The present study was designed to evaluate the association of interleukin-28 gene polymorphism with interleukin-28 cytokine levels in different viral genotypes among HCV patients in Yazd, Iran.

RESULT

The most prevalent genotype in chronic cases was genotype 3a, and the lowest one was 2/3a. There were statistically significant differences in genotype frequency between the two studied groups for IL-28B rs12979860C/T. The frequency of CC genotype of IL-28B at rs12979860 SNP was higher in spontaneously cleared patients in comparison with chronic HCV patients. Significant association was found when serum levels of IL28B were compared to various IL-28 genotypes. There was a significant difference between IL-28 polymorphism and HCV genotypes (p = 0.003).

Peripheral blood and hepatic Toll-like receptor 7 expression and interferon lambda 1 levels in chronic hepatitis C: Relation to virus replication and liver injury

BACKGROUND AND AIM

Toll-like receptor 7 (TLR7) can recognize single-stranded RNA viruses like hepatitis C virus (HCV) with subsequent induction of different interferon (IFN) types including IFN lambda (IFNL), which activate an immediate anti-viral response. However, the role of TLR7 in inflammation and fibrosis, characteristics of HCV-induced liver injury, is still controversial. The present work was designed to investigate the potential role of TLR7 and IFNL1 in chronic hepatitis C (CHC) in relation to viral replication and liver injury.

METHODS

Forty two treatment-naïve patients with CHC and 20 healthy subjects were enrolled in the study. TLR7 expression on peripheral blood CD14+ monocytes was studied by color flow cytometry and the frequency of TLR7+CD14+ cells was expressed as percentage of total monocyte count. Quantification of IFNL1 levels in serum was determined using enzyme-linked immunosorbant assay. Liver biopsies were examined for assessment of histological activity grade (A0-A3) and fibrosis stage (F0-F4) according to METAVIR scoring system as well as steatosis grade. Immunohistochemical staining was performed using human antibodies against TLR7 and IFNL1 and was scored semi-quantitatively (score 0-3). Hepatic expression of TLR7 and IFNL1 was further classified using a two-grade scale as low expression (score 0 or 1) and high expression (score 2 or 3).

RESULTS

Percentages of circulating TLR7+CD14+ monocytes and serum IFNL1 levels were significantly higher in patients with CHC than in healthy controls (P = 0.025 and P < 0.001 respectively) and were positively correlated with corresponding hepatic TLR7 and IFNL1 expression (P < 0.001 and P = 0.010 respectively). Significantly lower peripheral blood and hepatic TLR7 expression and IFNL1 levels were found in patients with viral loads between 200,000-600,000 IU/ml and >600,000 IU/ml than in those with viral load <200,000 IU/ml (P < 0.05), in patients with severe necroinflammation than in those with mild-to-moderate necroinflammation (P < 0.05) and in patients with advanced fibrosis than in those with early fibrosis (P < 0.01). Also, changes in TLR7 expression and IFNL1 production in peripheral blood and the liver were inversely correlated with serum levels of aspartate and alanine aminotransferases (P < 0.05) and HCV RNA (P < 0.01), histological activity grade (P < 0.01) and fibrosis stage (P < 0.01). By plotting receiver operating characteristics (ROC) curve, serum IFNL1 showed higher sensitivity and specificity than percentages of circulating TLR7+CD14+ monocytes in discriminating patients with CHC according to the severity of hepatic necroinflammation (area under the curve (AUC) = 0.901 vs. 0.816 respectively) and fibrosis (AUC = 0.971 vs. 0.825 respectively) at a cut-off value of 44.75 pg/ml and 10.25% respectively.

CONCLUSIONS

TLR7 activation and IFNL1 production in CHC may play an important role in controlling viral replication and limiting hepatic inflammation and fibrosis and their downregulation may result in viral persistence and disease progression. The immunoregulatory role of TLR7-IFNL1 pathway in the pathogenesis of chronic HCV infection should be further studied. Clinical trials with a large number of patients are needed to assess the usefulness of serum IFNL1 as a potential biomarker for severity of liver injury in chronic HCV infection and other liver diseases.

Association of serum interferon-λ3 levels with hepatocarcinogenesis in chronic hepatitis C patients treated with direct-acting antiviral agents

AIM

Although the efficacy of hepatitis C virus (HCV) treatment is improved dramatically by direct-acting antiviral agents (DAAs), the assessment of hepatocellular carcinoma (HCC) remains important. Interferon lambda 3 (IFN-λ3) is associated with liver fibrosis and inflammation in chronic hepatitis C (CHC) patients, but its impact on carcinogenesis remains controversial and little is known about its effects after viral clearance. To determine the contribution of IFN-λ3 to hepatocarcinogenesis after HCV clearance, we analyzed IFNL3 genotypes and serial serum IFN-λ3 levels in CHC patients who achieved sustained virologic responses (SVR).

METHODS

This study comprised 201 CHC patients treated with DAAs. Serum samples were collected sequentially and IFN-λ3 levels were quantified by chemiluminescence enzyme immunoassay. The IFNL3 polymorphism (rs8099917) was genotyped in 195 patients.

RESULTS

One hundred and twenty-five patients were rs8099917 T/T and 70 were non-T/T. Serum IFN-λ3 levels did not differ significantly with IFNL3 genotype, dropped markedly by 1 week and remained low up to 24 weeks after the end of treatment. Interferon-λ3 levels were significantly higher after viral clearance in patients who developed HCC and were associated with a higher potential for hepatocarcinogenesis, such as a higher frequency of non-hypervascular hypointensive nodules (P = 0.046), higher stages of liver fibrosis (P < 0.001), and higher post-treatment levels of Wisteria floribunda agglutinin positive Mac-2 binding protein (P < 0.001) and alanine aminotransferase (P < 0.001).

CONCLUSIONS

Serum IFN-λ3 levels after HCV clearance are associated with the potential for HCC development. Interferon-λ3 could be helpful for elucidating the relationships among immunologic status, liver fibrosis, liver inflammation, and hepatocarcinogenesis, after achieving SVR.

IL28B, IL29 and micro-RNA 548 in subacute sclerosing panencephalitis as a rare disease

Subacute sclerosing panencephalitis (SSPE) is a progressive neurodegenerative disease which affects children and young adults, caused by a persistent infection of defective measles virus. IFN-λs (IL-28A, IL-28B and IL-29) are a group of cytokines mediating antiviral responses. It has been shown that IL-29 levels are significantly higher in infected cells with defective measles virus. IL-29 expression is thought to be regulated at post-transcriptional level and miRNA-548 family targets the 3'UTR of the IFNL1 gene. Impaired immune system has an important role as well as viral factors in SSPE. The aim of our study investigates whether IL-28B, IL-29 levels and gene polymorphisms contribute to the damaged immune response leading to the development of SSPE. Also possible association of miR-548 family with IL-29 and SSPE is explored. Frequencies of rs12979860, rs8099917, rs30461, serum levels of IL-28B, IL-29 and expression levels of miR-548b, miR-548c, miR-548i are determined at 64 SSPE patients and 68 healthy controls. Serum IL-29 levels are statistically significant higher in SSPE patients. Allele frequencies of rs8099917 are statistically significant higher in SSPE patients and resulted G allele is found to increase 2.183-fold risk of SSPE. The expression levels of miR-548b-5p, miR-548c-5p and miR-548i are found to be statistically significant higher in SSPE patients. Dramatically increased level of IL-29 seen in patient group indicates that the elevated miR-548 expression is compensatory result of the over-activated immune system response. Further studies referred to IL28, IL29 and related miRNA's will be enlightened the pathogenesis of SSPE.

Mononuclear phagocyte system in hepatitis C virus infection

The mononuclear phagocyte system (MPS), which consists of monocytes, dendritic cells (DCs), and macrophages, plays a vital role in the innate immune defense against pathogens. Hepatitis C virus (HCV) is efficient in evading the host immunity, thereby facilitating its development into chronic infection. Chronic HCV infection is the leading cause of end-stage liver diseases, liver cirrhosis, and hepatocellular carcinoma. Acquired immune response was regarded as the key factor to eradicate HCV. However, innate immunity can regulate the acquired immune response. Innate immunity-derived cytokines shape the adaptive immunity by regulating T-cell differentiation, which determines the outcome of acute HCV infection. Inhibition of HCV-specific T-cell responses is one of the most important strategies for immune system evasion. It is meaningful to illustrate the role of innate immune response in HCV infection. With the MPS being the important factor in innate immunity, therefore, understanding the role of the MPS in HCV infection will shed light on the pathophysiology of chronic HCV infection. In this review, we outline the impact of HCV infection on the MPS and cytokine production. We discuss how HCV is detected by the MPS and describe the function and impairment of MPS components in HCV infection.

Impact of the Uridine⁻Cytidine Kinase Like-1 Protein and IL28B rs12979860 and rs8099917 SNPs on the Development of Hepatocellular Carcinoma in Cirrhotic Chronic Hepatitis C Patients-A Pilot Study

Background and objectives: The hepatitis C virus (HCV) is the major causative agent of hepatocellular carcinoma (HCC) in the western world. The efficacy of surveillance programs for early detection of HCC is not satisfactory: many tumors are diagnosed at the late, incurable stages. Therefore, there is a need in reliable prognostic markers for the proper follow-up of HCV-positive patients. The aim of the present study was to assess the prognostic value of the uridine⁻cytidine kinase-like protein 1 (UCKL-1), a putative oncoprotein, together with genetically determined polymorphisms in the interleukin 28B (IL28B) gene (rs12979860, rs8099917) in the development of HCC in HCV-positive cirrhotic patients. Materials and Methods: We included 32 HCV cirrhotic patients, 21 (65.6%) of whom had HCC. The expression of UCKL-1 was assessed in liver tissue sections, using immunohistochemistry. For IL28B rs12979860 and rs8099917 genotype analysis, the corresponding genomic regions were amplified by polymerase chain reaction (PCR) with appropriate primers. Results: We have found that UCKL-1 expression was significantly increased in HCC (p = 0.003). The presence of rs8099917 TT single-nucleotide polymorphism (SNP) elevated the chances of HCC manifestation more than sevenfold (OR = 7.3, p = 0.0273). The presence of rs12979860 CC SNP also heightened HCC chances more than sevenfold (OR = 7.5, p = 0.0765). Moreover, in the HCC group, a combination of IL28B rs12979860 non-TT and rs8099917 TT genotypes was observed more often, compared with the non-HCC group. Other combinations of IL28B rs12979860 and rs8099917 SNIPs were associated with a reduced risk of HCC development, approximately at the same extent. Conclusions: The presence of IL28B rs8099917 TT and rs12979860 CC SNPs, but not the intensity of UCKL-1 expression, is strongly associated with increased chances of HCC development in HCV-positive cirrhotic patients.

Identifying causal variants at the interferon lambda locus in case-control studies: Utilizing non-synonymous variant rs117648444 to probe the role of IFN-λ4

Genetic variants at the interferon lambda (IFNL) locus have been associated with several human phenotypes in both disease and health. In chronic hepatitis C virus (HCV) infections, where the IFNL variants were first identified to be associated with response to interferon-α-ribavirin therapy, the available data clearly suggests that the causal variant could be the dinucleotide polymorphism rs368234815 that causes an open reading frame-shift in the IFNL4 gene resulting in expression of a functional IFN-λ4, a new type III IFN. In other human diseases/phenotypes where IFNL variants have been recently associated with, the causal mechanism remains unclear. In vitro evidence has shown that other IFNL variants (rs28416813, rs4803217) may regulate expression of another type III IFN, IFN-λ3. Therefore, expression of a functional IFN-λ4 and quantitative differences in IFN-λ3 expression are two potential causal mechanisms behind the observed phenotypes. Since these two potential causal mechanisms involve features of mutual exclusivity and overlapping functions, it is difficult to differentiate one from the other, in vivo, in absence of other implicating evidences. In addition, the strong linkage disequilibrium (LD) observed in many populations at the IFNL locus makes it difficult to tease out the actual functional/causal variants responsible for the phenotypes. The non-synonymous single nucleotide polymorphism rs117648444 that alters the activity of IFN-λ4 and the LD structure in the IFNL region which leads to a confounding effect of rs117648444 on other IFNL variants, provide us with additional tools in case-control studies to probe the role of IFN-λ4.

IFNΛ3/4 locus polymorphisms and IFNΛ3 circulating levels are associated with COPD severity and outcomes

BACKGROUND

Interferon lambdas (IFNLs) have important anti-viral/bacterial and immunomodulatory functions in the respiratory tract. How do IFNLs impact COPD and its exacerbations?

METHODS

Five hundred twenty eight patients were recruited in a prospective observational multicentre cohort (PROMISE) study. The genetic polymorphisms (rs8099917 and rs12979860) within the IFNL3/4 gene region and circulating levels of IFNL3 in COPD patients were determined and associated with disease activity and outcome during a median follow-up of 24 months.

RESULTS

The GG genotype significantly influenced severe exacerbation rate (42 vs. 23%; p = 0.032) and time to severe exacerbation (HR = 2.260; p = 0.012). Compared to the TT or TG genotypes, the GG genotype was associated with severe dyspnoea (modified medical research council score ≥ median 3; 22 vs 42%, p = 0.030). The CC genotype of the rs12979860 SNP was associated with a poorer prognosis (body mass index, airflow obstruction, dyspnea and exercise capacity index ≥ median 4; 46 vs. 36% TC vs. 20.5% TT; p = 0.031). Patients with stable COPD and at exacerbation had significantly lower circulating IFNL3 compared to healthy controls (p < 0.001 and p < 0.001, respectively). Circulating IFNL3 correlated to post-bronchodilator FEV1%predicted and the tissue maturation biomarker Pro-collagen 3.

CONCLUSION

IFNL3/4 polymorphisms and circulating IFNL3 may be associated with disease activity and outcomes in COPD.

TRIAL REGISTRATION

Clinical Trial registration http://www.isrctn.com/ identifier ISRCTN99586989 on 16 April 2008.

Interleukin 28B rs12979860 genotype and Human Immunodeficiency Virus type 1: Susceptibility, AIDS development and therapeutic outcome

Human Immunodeficiency Virus type 1 (HIV-1) infection and progression varies widely among individuals. Interferon-λ3 exerts anti-HIV function by activating JAK/STAT pathway-mediated innate immunity. Therefore, we aimed to investigate the association between single nucleotide polymorphisms of the interleukin 28B (IL28B) gene, and the risk of acquisition, AIDS development and therapeutic outcome of HIV-1 in a Moroccan population. A total of 266 HIV-1 seropositive and 158 HIV-1 seronegative subjects were enrolled. Genotyping of rs12979860 of the IL28B was performed using a predesigned TaqMan SNP genotyping assay. No significant association was found between IL28B rs12979860 polymorphism and susceptibility to HIV-1 infection and AIDS development (p > .05). However, in HIV-1 treated patients carrying CC genotype had a more pronounced high levels of CD4+ T-cell compared to subjects with TT genotype (p = .0004). Interestingly, regarding HIV-1 viral load no significant differences between IL28B genotypes in treated and untreated patients were observed (p < .05). IL28B rs12979860 polymorphism not influences the susceptibility to HIV-1 and the AIDS development. However, this polymorphism may affect the response to treatment as measured by CD4+ T cell counts.

Association of Single-Nucleotide Polymorphisms in Immune-Related Genes with Development of Dengue Hemorrhagic Fever in a Mexican Population

Single-nucleotide polymorphisms (SNPs) occurring in immune-related genes have been associated with risk or protection for development of dengue, depending on ethnicity. Here, we genotyped seven SNPs located in immune response-related genes to identify their association with severe forms of dengue in patients from an endemic region in Mexico. One hundred and thirty-eight patients with dengue fever (DF), thirty-one dengue hemorrhagic fever (DHF) patients, as well as 304 healthy donors were genotyped by using a TaqMan-based approach. SNP analysis, including rs1800629 (TNF), rs4804803 (CD209), rs2780831 (JAK1), rs1801274 (FCGR2A), rs231775 (CTLA4), rs12979860, and rs8099917 (IFNL3), was performed. The rs1800629 A-allele in the TNF gene was associated with an increased risk of DHF (OR = 3.4, CI = 1.235-9.284 p = 0.0212) whereas SNPs rs4804803, rs2780831, rs1801274, rs231775, rs12979860, and rs8099917 showed no association in this cohort. These results show that allelic variations in TNF can play an important role in the development of DHF. However, the lack of association between all remaining SNPs and DHF suggests that the genetic background might directly modify the role of these immune-related molecules, leading to the milder illness often observed in a Mexican population.

Both Hepatitis C Virus-Specific T Cell Responses and IL28B rs12979860 Single-Nucleotide Polymorphism Genotype Influence Antihepatitis C Virus Treatment Outcome in Patients with Chronic Hepatitis C

Despite new treatments for hepatitis C virus (HCV) infection, IFNα-based regimens still have clinical relevance in special populations of patients and remain the only therapeutic option for many patients. We sought to elucidate the interplay between two relevant factors (IL28B polymorphism and T cell immune responses) involved in the outcome of this therapy in HCV-infected patients. We evaluated 38 patients infected with HCV genotype 1-17 coinfected with HIV-who were undergoing a full course of pegIFNα/RBV therapy. The interdependence and roles of T cell-mediated immune responses and IL28B rs12979860 single-nucleotide polymorphism genotype as predictors of virological response to anti-HCV treatment in patients with chronic hepatitis C were evaluated using nonparametric tests. Factors associated with rapid virological response (RVR) in univariate analysis were presence of CD4 T cell response against NS3 HCV protein, low baseline HCV-RNA, and IL28B CC genotype. Factors associated with sustained virological response (SVR) in univariate analysis were IL28B CC genotype, low baseline HCV-RNA, and presence of CD4 response against NS2. In the multivariate analysis, low baseline HCV-RNA and NS3-specific CD4 response showed a clear trend toward association with RVR (P = 0.09 and P = 0.07, respectively). Regarding SVR, IL28B CC genotype was the strongest predictor (P = 0.02), with presence of NS2-specific CD4 response showing a clear trend (P = 0.09). HCV-specific T cell response influences the outcome of pegIFNα/RBV therapy regardless of IL28B genotype. HCV-specific T cell responses (adaptive immunity) seem to influence viral clearance both in the short and long term during therapy (RVR and SVR), whereas the influence of the IL28B genotype (innate immunity) may be more relevant to the long-lasting therapeutic effect (SVR).

IFN-λ3, not IFN-λ4, likely mediates IFNL3-IFNL4 haplotype-dependent hepatic inflammation and fibrosis

Genetic variation in the IFNL3-IFNL4 (interferon-λ3-interferon-λ4) region is associated with hepatic inflammation and fibrosis. Whether IFN-λ3 or IFN-λ4 protein drives this association is not known. We demonstrate that hepatic inflammation, fibrosis stage, fibrosis progression rate, hepatic infiltration of immune cells, IFN-λ3 expression, and serum sCD163 levels (a marker of activated macrophages) are greater in individuals with the IFNL3-IFNL4 risk haplotype that does not produce IFN-λ4, but produces IFN-λ3. No difference in these features was observed according to genotype at rs117648444, which encodes a substitution at position 70 of the IFN-λ4 protein and reduces IFN-λ4 activity, or between patients encoding functionally defective IFN-λ4 (IFN-λ4-Ser70) and those encoding fully active IFN-λ4-Pro70. The two proposed functional variants (rs368234815 and rs4803217) were not superior to the discovery SNP rs12979860 with respect to liver inflammation or fibrosis phenotype. IFN-λ3 rather than IFN-λ4 likely mediates IFNL3-IFNL4 haplotype-dependent hepatic inflammation and fibrosis.

Interferon Lambda: Modulating Immunity in Infectious Diseases

Interferon lambdas (IFN-λs; IFNL1-4) modulate immunity in the context of infections and autoimmune diseases, through a network of induced genes. IFN-λs act by binding to the heterodimeric IFN-λ receptor (IFNLR), activating a STAT phosphorylation-dependent signaling cascade. Thereby hundreds of IFN-stimulated genes are induced, which modulate various immune functions via complex forward and feedback loops. When compared to the well-characterized IFN-α signaling cascade, three important differences have been discovered. First, the IFNLR is not ubiquitously expressed: in particular, immune cells show significant variation in the expression levels of and susceptibilities to IFN-λs. Second, the binding affinities of individual IFN-λs to the IFNLR varies greatly and are generally lower compared to the binding affinities of IFN-α to its receptor. Finally, genetic variation in the form of a series of single-nucleotide polymorphisms (SNPs) linked to genes involved in the IFN-λ signaling cascade has been described and associated with the clinical course and treatment outcomes of hepatitis B and C virus infection. The clinical impact of IFN-λ signaling and the SNP variations may, however, reach far beyond viral hepatitis. Recent publications show important roles for IFN-λs in a broad range of viral infections such as human T-cell leukemia type-1 virus, rotaviruses, and influenza virus. IFN-λ also potentially modulates the course of bacterial colonization and infections as shown for Staphylococcus aureus and Mycobacterium tuberculosis. Although the immunological processes involved in controlling viral and bacterial infections are distinct, IFN-λs may interfere at various levels: as an innate immune cytokine with direct antiviral effects; or as a modulator of IFN-α-induced signaling via the suppressor of cytokine signaling 1 and the ubiquitin-specific peptidase 18 inhibitory feedback loops. In addition, the modulation of adaptive immune functions via macrophage and dendritic cell polarization, and subsequent priming, activation, and proliferation of pathogen-specific T- and B-cells may also be important elements associated with infectious disease outcomes. This review summarizes the emerging details of the IFN-λ immunobiology in the context of the host immune response and viral and bacterial infections.

The Role of Type III Interferons in Hepatitis C Virus Infection and Therapy

The human interferon (IFN) response is a key innate immune mechanism to fight virus infection. IFNs are host-encoded secreted proteins, which induce IFN-stimulated genes (ISGs) with antiviral properties. Among the three classes of IFNs, type III IFNs, also called IFN lambdas (IFNLs), are an essential component of the innate immune response to hepatitis C virus (HCV). In particular, human polymorphisms in IFNL gene loci correlate with hepatitis C disease progression and with treatment response. To date, the underlying mechanisms remain mostly elusive; however it seems clear that viral infection of the liver induces IFNL responses. As IFNL receptors show a more restricted tissue expression than receptors for other classes of IFNs, IFNL treatment has reduced side effects compared to the classical type I IFN treatment. In HCV therapy, however, IFNL will likely not play an important role as highly effective direct acting antivirals (DAA) exist. Here, we will review our current knowledge on IFNL gene expression, protein properties, signaling, ISG induction, and its implications on HCV infection and treatment. Finally, we will discuss the lessons learnt from the HCV and IFNL field for virus infections beyond hepatitis C.

Modulation of Immune Responses to Herpes Simplex Virus Type 1 by IFNL3 and IRF7 Polymorphisms: A Study in Alzheimer's Disease

Herpes simplex virus type 1 (HSV-1) has long been suspected to play a role in Alzheimer's disease (AD), the most common form of dementia. IFN-lambda (IFN-λ) is one of the key cytokine in innate antiviral defenses and, in particular, has an appreciable antiviral activity against HSV-1 infection. IFN-λ expression is regulated by the interaction between two different proteins: Mediator Complex 23 (MED23) and Interferon-Responsive Transcription Factor 7 (IRF7); single nucleotide polymorphisms (SNPs) in these genes as well as in IFNL3 were shown to be differently distributed in AD patients. In this study, allelic discrimination analysis for IFNL3 rs12979860, MED23 rs3756784, and IRF7 rs6598008, as well as IFN-λ serum concentration and anti-HSV-1 antibody (Ab) titers were performed in 79 AD patients, 57 mild cognitive impairment (MCI) individuals, and 81 healthy controls (HC) who were HSV-1-seropositive. Results showed that INF-λ serum concentration was increased in AD and MCI carrying the IFNL3 T allele compared to HC (AD versus HC: p = 0.014; MCI versus HC: p = 0.029), with the highest anti-HSV-1 Ab titers seen in AD patients carrying the IFNL3 CC genotype (p = 0.012 versus HC). Notably, anti-HSV-1 Ab titers were higher in AD and MCI individuals carrying the IRF7 AA genotype compared to HC (p = 0.018 for both). MED23 polymorphisms did not show any statistical association either with serum IFN-λ or with anti-HSV-1 Ab. Data herein suggest that the IFNL3 rs12979860 and IRF7 rs6598008 polymorphisms modulate immune responses against HSV-1 via their effect on the IFN-λ pathway. These results help to clarify the possible role of HSV-1 infection in AD pathogenesis.

Type III Interferons in Hepatitis C Virus Infection

The interferon (IFN)-λ family of type III cytokines includes the closely related interleukin (IL)-28A (IFN-λ2), IL-28B (IFN-λ3), and IL-29 (IFN-λ1). They signal through the Janus kinases (JAK)-signal transducers and activators of transcription pathway and promote an antiviral state by the induction of expression of several interferon-stimulated genes (ISGs). Contrary to type I IFNs, the effect of IFN-λ cytokines is largely limited to epithelial cells due to the restricted pattern of expression of their specific receptor. Several genome-wide association studies have established a strong correlation between polymorphism in the region of IL-28B gene (encoding for IFN-λ3) and both spontaneous and therapeutic IFN-mediated clearance of hepatitis C virus (HCV) infection, but the mechanism(s) underlying this enhanced viral clearance are not fully understood. IFN-λ3 directly inhibits HCV replication, and in vitro studies suggest that polymorphism in the IFN-λ3 and its recently identified overlapping IFN-λ4 govern the pattern of ISGs induced upon HCV infection of hepatocytes. IFN-λ can also be produced by dendritic cells, and apart from its antiviral action on hepatocytes, it can regulate the inflammatory response of monocytes/macrophages, thus acting at the interface between innate and adaptive immunity. Here, we review the current state of knowledge about the role of IFN-λ cytokines in mediating and regulating the immune response during acute and chronic HCV infections.

Antibodies to HBV surface antigen in relation to interferon-λ3 in hemodialysis patients

AIM

To investigate circulating IFN-λ3 and IFNL3 polymorphisms in hemodialysis (HD) patients differing in HBV surface antigen antibody (anti-HBs) production.

METHODS

The study included 106 HBV-vaccinated HD patients (88 developed anti-HBs) and 36 HBV-infected HD subjects (27 developed anti-HBs). Plasma IFN-λ3 (enzyme-linked immunosorbent assay) and rs12979860 (C>T) and rs8099917 (T>G) in IFNL3 (high-resolution melting curve analysis) were analyzed with regard to the association with anti-HBs production in response to HBV vaccination or infection. The results were adjusted for gender, age, cause of renal disease, dialysis vintage, dialysis modality, IFN-λ3, and 25(OH)D as appropriate.

RESULTS

HBV vaccine responders had higher circulating IFN-λ3 (ng/L) than non-responders (120, 36-233 vs. 53, 33-109, P<0.000001). Patients who generated anti-HBs after HBV infection also had higher circulating IFN-λ3 levels than those who did not (133, 35-215 vs. 71, 9-229, P=0.043). The IFN-λ3 concentration correlated with the anti-HBs titer in vaccinated (r=0.614, P<0.000001) and infected patients (r=0.589, P=0.0002). Plasma IFN-λ3 was the only significant indicator of responsiveness to HBV vaccination (adjusted P=0.018) and remained the only significant associate for the development of post-infection anti-HBs (adjusted P=0.049). A plasmaIFN-λ3 level of 85.5ng/L was thecut-off value for theprognosis of an anti-HBs titer below vs. equal to or over 10IU/L in the entire group of HD patients (ROC sensitivity 68.7%, specificity 85.2%, and AUC 0.827). Significant associations were not found between IFN-λ3 and IFNL3 rs12979860. Subjects treated with low flux HD that harbored the TT genotype in rs8099917 showed higher IFN-λ3 levels than patients bearing the G allele in rs8099917 (139, 68-233 vs. 103, 9-208, P=0.049).

CONCLUSION

In HD patients, circulating IFN-λ3 strongly correlates with anti-HBs production after HBV vaccination and infection. IFNL3 rs8099917 polymorphisms seem to be associated with IFN-λ3 plasma levels in HD subjects.

IFN-λ3 polymorphism indirectly influences NK cell phenotype and function during acute HCV infection

Introduction

Polymorphisms in the type III interferon IFN‐λ3 and the killer cell immunoglobulin‐like receptor (KIR) genes controlling the activity of natural killer (NK) cells can predict spontaneous resolution of acute hepatitis C virus (HCV) infection. We hypothesized that IFN‐λ3 polymorphism may modulate NK cell function during acute HCV.

Methods

We monitored the plasma levels of type III IFNs in relation to the phenotype and the function of NK cells in a cohort of people who inject drugs (PWID) during acute HCV infection with different outcomes.

Results

Early acute HCV was associated with high variability in type III IFNs plasma levels and the favorable IFN‐λ3 CC genotype was associated with higher viral loads. Reduced expression of Natural Killer Group Protein 2A (NKG2A) was associated with lower IFN‐λ3 plasma levels and the CC genotype. IFN‐γ production by NK cells was higher in individuals with the CC genotype during acute infection but this did not prevent viral persistence. IFN‐λ3 plasma levels did not correlate with function of NK cells and IFN‐λ3 prestimulation did not affect NK cell activation and function.

Conclusions

These results suggest that IFN‐λ3 polymorphism indirectly influences NK cell phenotype and function during acute HCV but other factors may act in concert to determine the outcome of the infection.

Cellular Mechanism for Impaired Hepatitis C Virus Clearance by Interferon Associated with IFNL3 Gene Polymorphisms Relates to Intrahepatic Interferon-λ Expression

The single nucleotide polymorphism located within the IFNL3 (also known as IL28B) promoter is one of the host factors associated with hepatitis C virus (HCV) clearance by interferon (IFN)-α therapy; however the mechanism remains unknown. We investigated how IL28B gene polymorphism influences HCV clearance with infected primary human hepatocytes, liver biopsies, and hepatoma cell lines. Our study confirms that the rs12979860-T/T genotype has a strong correlation with ss469415590-ΔG/ΔG single nucleotide polymorphism that produces IFN-λ4 protein. We found that IFN-α and IFN-λ1 antiviral activity against HCV was impaired in IL28B T/T infected hepatocytes compared with C/C genotype. Western blot analysis showed that IL28B TT genotype hepatocytes expressed higher levels of IFN-λ proteins (IL28B, IL-29), preactivated IFN-stimulated gene (ISG) expression, and impaired Stat phosphorylation when stimulated with either IFN-α or IFN-λ1. Furthermore, we showed that silencing IFN-λ1 in T/T cell line reduced basal ISG expression and improved antiviral activity. Likewise, overexpression of IFN-λ (1 to 4) in C/C cells induced basal ISG expression and prevented IFN-α antiviral activity. We showed that IFN-λ4, produced at low level only in T/T cells induced expression of IL28B and IL-29 and prevented IFN-α antiviral activity in HCV cell culture. Our results suggest that IFN-λ4 protein expression associated with the IL28B-T/T variant preactivates the Janus kinase-Stat signaling, leading to impaired HCV clearance by both IFN-α and IFN-λ.

High MIG (CXCL9) plasma levels favours response to peginterferon and ribavirin in HCV-infected patients regardless of DPP4 activity

BACKGROUND & AIMS

Sustained virological response (SVR) following peginterferon (pegIFN) and ribavirin (RBV) treatment in hepatitis C virus (HCV)-infected patients has been linked with the IL28B genotype and lower peripheral levels of the CXCR3-binding chemokine IP-10 (CXCL10). To further improve the understanding of these biomarkers we investigated plasma levels of the other CXCR3-binding chemokines and activity of the dipeptidyl peptidase IV (DPP4, CD26) protease, which cleaves IP-10, in relation to treatment response.

METHODS

African-American and Caucasian HCV genotype 1-infected patients (n = 401) were treated with pegIFN/RBV for 48 weeks (ViraHep-C cohort). Pretreatment plasma levels of MIG (CXCL9), I-TAC (CXCL11) and the type III interferon IL29 were investigated by Luminex and DPP4 activity by using a luciferase assay.

RESULTS

Patients achieving SVR had higher baseline MIG plasma levels and lower DPP4 activity than non-SVR patients. MIG was higher in Caucasians, IL28B CC (rs1297860) genotype carriers and patients with higher ALT levels. MIG correlated with IP-10 in SVR patients, but not in non-SVRs. A high DPP4 activity correlated with higher IP-10 levels, while DPP4 activity was not associated with MIG or I-TAC levels.

CONCLUSIONS

The associations of MIG with SVR status and IL28B genotype imply that higher MIG plasma levels could reflect a beneficial immunological state for response to pegIFN/RBV treatment. The correlation between MIG and IP-10 observed only in SVR patients may contribute to a better treatment response, whereas this MIG/IP-10 balance might be disrupted in non-SVR patients because of the increased DPP4 cleavage of IP-10 into a dysfunctional form.

Relationship between IL28B gene rs8099917 polymorphism and SVR in Turkish patients with hepatitis C virus genotype 1

BACKGROUND AND OBJECTIVE

The hepatitis C virus (HCV) which infects 3% of the world's population is a global challenge. Recently, genome-wide association studies (GWAS) have identified that the IL28B gene rs8099917 polymorphism was associated with the response to the pegylated-interferon alpha/ribavirin (PegIFNα/RBV) combination therapy in patients infected with HCV genotype 1. IL28B gene rs8099917 polymorphism should be determined before beginning treatment of HCV-infected patients to predict an individual's response. The aims of this study were to analyze the correlation between IL28B gene rs8099917 (T/G) polymorphism and PegIFNα/RBV therapy outcome in the Turkish population.

METHODS

Genotypes of the IL28B gene rs8099917 (T/G) single nucleotide polymorphism (SNP) were determined in 308 patients with HCV infection by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. One group consisted of 148 patients with a sustained virological response (SVR), whereas the second group consisted of 160 nonresponders (non-SVR).

RESULTS

Allele and genotype associations of IL28B gene rs8099917 polymorphism with a sustained virological response were observed in comparisons between the SVR and non-SVR groups (P<0.001). In addition, the characteristics of the subjects did not differ between these two groups except for age and fibrosis stage (P<0.05). Additionally, neither SVR nor rs80999917 genotypes were associated by HCV RNA levels.

CONCLUSIONS

In conclusion, the rs8099917 polymorphism was thus found strongly associated with a sustained virological response to therapy in Turkish patients infected with HCV genotype 1. Consequently, we suggest determining IL28B gene rs8099917 polymorphism of patients with HCV genotype 1 before onset of treatment.

IFNL3 mRNA structure is remodeled by a functional non-coding polymorphism associated with hepatitis C virus clearance

Polymorphisms near the interferon lambda 3 (IFNL3) gene strongly predict clearance of hepatitis C virus (HCV) infection. We analyzed a variant (rs4803217 G/T) located within the IFNL3 mRNA 3' untranslated region (UTR); the G allele (protective allele) is associated with elevated therapeutic HCV clearance. We show that the IFNL3 3' UTR represses mRNA translation and the rs4803217 allele modulates the extent of translational regulation. We analyzed the structures of IFNL3 variant mRNAs at nucleotide resolution by SHAPE-MaP. The rs4803217 G allele mRNA forms well-defined 3' UTR structure while the T allele mRNA is more dynamic. The observed differences between alleles are among the largest possible RNA structural alterations that can be induced by a single nucleotide change and transform the UTR from a single well-defined conformation to one with multiple dynamic interconverting structures. These data illustrate that non-coding genetic variants can have significant functional effects by impacting RNA structure.

Up-regulation of A20/ABIN1 contributes to inefficient M1 macrophage polarization during Hepatitis C virus infection

BACKGROUND

Anti-hepatitis C virus (HCV) responses are often accompanied by an increase in alanine aminotransferase levels in HCV-infected patients, indicating that inflammatory responses are compromised by the virus. Additionally, inflammation is associated with M1-polarizated macrophages, which secrete cytokines such as tumor necrosis factor-α, interleukin-1, and interleukin-12, and present antigens through phagocytosis. HCV-encoded proteins are presented as specific viral antigens in particular infectious steps that influence the immune response. For instance, HCV antigens impact macrophage PD-1 and Tim-3 expression, and contribute to impaired viral clearance. Furthermore, circulatory HCV antigens from infected patients inhibit dendritic cell differentiation, which raises the possibility that HCV antigens may also interfere with macrophage polarization.

METHODS

In this study, the impact of HCV antigen stimulation on M1-polarized macrophages was investigated. The influence of HCV antigens was evaluated by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Specific changes were investigated clinically by flow cytometry and immunofluorescence. Effects of NF-κB during the process were analyzed by western blot.

RESULTS

HCV infection dampened M1 macrophage polarization ex vivo and in vitro. After antigen stimulation, NF-κB signaling was suppressed by the up-regulation of A20 and A20-binding inhibitor of NF-κB binding protein, which likely leads to a variation of functional molecules such as tumor necrosis factor-α, CD163, matrix metalloproteinases, transferrin receptor-1, and CD100, reflecting an anti-inflammatory reaction against M1-polarization.

CONCLUSION

HCV antigens stimulation up-regulates A20/A20-binding inhibitor of NF-κB binding protein expression, which consequently contributes to inefficient M1 macrophage polarization.

Association of serum IFN-λ3 with inflammatory and fibrosis markers in patients with chronic hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV) is one of the major causes of liver cancer. The single nucleotide polymorphisms within the IFNL3 gene, which encodes interferon (IFN)-λ(3), are strongly associated with the response to pegylated IFN-α (PEG-IFN-α) plus ribavirin (RBV) therapy in chronic hepatitis C (C-CH) patients. However, the roles of IFN-λ(3) in chronic HCV infection are still elusive. In this study, we aimed to identify clinical and immunological factors influencing IFN-λ(3) and evaluated whether serum IFN-λ(3) levels are involved or not involved in the response to PEG-IFN-α plus RBV therapy.

METHODS

We enrolled 119 C-CH patients with HCV genotype 1 infection who underwent 48 weeks of PEG-IFN-α plus RBV therapy. As controls, 23 healthy subjects and 56 patients with non-HCV viral hepatitis were examined. Serum IFN-λ(3) was quantified by chemiluminescence enzyme immunoassay, and 27 cytokines or chemokines were assayed by the multiplexed BioPlex system.

RESULTS

Serum IFN-λ(3) levels were higher in C-CH patients or acute hepatitis E patients than in healthy volunteers. Such levels did not differ between the IFNL3 genotypes. In C-CH patients, serum IFN-λ(3) was positively correlated with aspartate aminotransferase, alanine aminotransferase, α-fetoprotein, histological activity, fibrosis index, IFN-γ-inducible protein 10, and platelet-derived growth factor. Multivariate analysis showed that IFNL3 single nucleotide polymorphisms, fibrosis score, and macrophage inflammatory protein 1α were involved in the sustained viral clearance in PEG-IFN-α plus RBV therapy; however, serum IFN-λ(3) levels were not involved.

CONCLUSION

Serum IFN-λ(3) levels are increased in C-CH patients regardless of the IFNL3 genotype. IFN-λ(3) is a biomarker reflecting the activity and fibrosis of liver disease, but is not correlated with the responsiveness to PEG-IFN-α plus RBV therapy.

Impaired induction of interleukin 28B and expression of interferon λ 4 associated with nonresponse to interferon-based therapy in chronic hepatitis C

BACKGROUND AND AIM

Interferon (IFN) λ plays an important role in innate immunity to protect against hepatitis C viral (HCV) infection. Single nucleotide polymorphisms (SNPs) near IL28B (IFNλ3) are strongly associated with treatment response to IFNα therapy in chronic hepatitis C (CHC) patients. Recently, IFNλ4 related to IL28B-unfavorable allele was discovered. However, the impact of IFNλs on CHC is unknown. We aimed to investigate the mechanism underlying responsiveness to IFN-based therapy in CHC associated with SNPs near IL28B.

METHODS

We evaluated the basal mRNA levels and ex-vivo induction of IFNλ expression including IFNλ4 in peripheral blood mononuclear cells (PBMCs) from 50 CHC patients treated with pegylated-IFNα/RBV. Furthermore, we investigated the effect of IFNλ4 on induction of IL28B in vitro.

RESULTS

When PBMCs were stimulated with IFNα and polyinosinic-polycytidylic acid, IL28B induction was significantly lower in patients with IL28B-unfavorable genotype (rs12979860 CT/TT) than those with IL28B-favorable genotype (rs12979860 CC; P=0.049). IL28B induction was lower in nonresponders than in relapsers (P = 0.04), and it was also lower in nonsustained virological responder patients for triple therapy including NS3 protease inhibitors. IFNλ4 mRNA was detected in 12 of 26 patients with IL28B-unfavorable SNP, and IFNλ4 expression was associated with lower IL28B induction in patients with IL28B-unfavorable genotype (P=0.04) and nonresponse to IFNα therapy (P=0.003). Overexpression of IFNλ4 suppressed IL28B induction and promoter activation.

CONCLUSIONS

Impaired induction of IL28B, related to IFNλ4 expression in PBMCs of IL28B-unfavorable patients, is associated with nonresponse to IFNα-based therapy for hepatitis C viral infection.

Prevalence of Thymine--Adenine Dinucleotide Repeat, IL28B and IFNL4 in Thai Population and Correlation with Spontaneous Clearance and Treatment Outcome of Hepatitis C Infection

BACKGROUND

The interleukin-28B (IL28B) gene polymorphism is a strong baseline predictor of sustained virological response (SVR) in hepatitis C virus (HCV) treatment. The length of thymine--adenine dinucleotide repeats, or (TA)n, in the regulatory region of IL28B can affect interferon transcription. In order to determine predictive values in HCV infection, we explored the correlation among factors including (TA)n genotypes, clinical features, interferon-λ-3 (IFNL3) and interferon-λ-4 (IFNL4) polymorphisms, and HCV treatment outcome.

METHODS

Sera from 492 patients with chronic HCV infection, 101 individuals with spontaneous HCV clearance and 123 healthy blood donors (control group) were analyzed. Genotyping of the (TA)n was performed by direct sequencing. The rs12979860 (IFNL3) was identified using nested PCR and sequencing, while ss469415590 (IFNL4) was identified by real-time PCR.

RESULTS

The distribution of (TA)n was similar between individuals with spontaneous HCV clearance and chronic HCV infection, but differed significantly from healthy controls. Individuals with both (TA)n alleles ≥ 12 had significantly higher SVR rate compared to individuals with at least one (TA)n <12 allele. This strong correlation was seen for patients infected with HCV-1, HCV-3, and HCV-6. The (TA)n genotypes were not associated with HCV viral load, ALT levels and liver stiffness, but were correlated with platelet counts (p<0.001). In contrast, rs12979860 (CC) and ss469415590 (TT/TT) genotypes were associated with higher SVR rated only in patients with HCV-1.

CONCLUSIONS

The (TA)n genotypes were not associated with spontaneous clearance of HCV infection but associated with treatment response in patients infected with HCV-1, HCV-3 and HCV-6. In contrast, IFNL3 and IFNL4 polymorphisms were predictive of treatment outcome only for patients infected with HCV-1.

IL28B is associated with outcomes of chronic HBV infection

PURPOSE

The role of IL28B gene variants and expression in hepatitis B virus (HBV) infections are not well understood. Here, we evaluated whether IL28B gene expression and rs12979860 variations are associated with HBV outcomes.

MATERIALS AND METHODS

IL28B genetic variations (rs12979860) were genotyped by pyrosequencing of DNA samples from 137 individuals with chronic HBV infection [50 inactive carriers (IC), 34 chronic hepatitis B (CHB), 27 cirrhosis, 26 hepatocellular carcinoma (HCC)], and 19 healthy controls. IL28A/B mRNA expression in peripheral blood mononuclear cells was determined by qRT-PCR, and serum IL28B protein was measured by ELISA.

RESULTS

Patients with IL28B C/C genotype had greater IL28A/B mRNA expression and higher IL28B protein levels than C/T patients. Within the various disease stages, compared to IC and healthy controls, IL28B expression was reduced in the CHB, cirrhosis, and HCC cohorts (CHB vs. IC, p=0.02; cirrhosis vs. IC, p=0.01; HCC vs. IC, p=0.001; CHB vs. controls, p<0.01; cirrhosis vs. controls, p<0.01; HCC vs. controls, p<0.01). When stratified with respect to serum HBV markers in the IC and CHB cohorts, IL28B mRNA and protein levels were higher in HBeAg-positive than negative individuals (p=0.01). Logistic regression analysis revealed that factors associated with high IL28B protein levels were C/C versus C/T genotype [p=0.016, odds ratio (OR)=0.25, 95% confidence interval (CI)=0.08-0.78], high alanine aminotransferase values (p<0.001, OR=8.02, 95% CI=2.64-24.4), and the IC stage of HBV infection (p<0.001).

CONCLUSION

Our data suggest that IL28B genetic variations may play an important role in long-term development of disease in chronic HBV infections.

Hepatitis C virus and antiviral innate immunity: Who wins at tug-of-war?

Hepatitis C virus (HCV) is a major human pathogen of chronic hepatitis and related liver diseases. Innate immunity is the first line of defense against invading foreign pathogens, and its activation is dependent on the recognition of these pathogens by several key sensors. The interferon (IFN) system plays an essential role in the restriction of HCV infection via the induction of hundreds of IFN-stimulated genes (ISGs) that inhibit viral replication and spread. However, numerous factors that trigger immune dysregulation, including viral factors and host genetic factors, can help HCV to escape host immune response, facilitating viral persistence. In this review, we aim to summarize recent advances in understanding the innate immune response to HCV infection and the mechanisms of ISGs to suppress viral survival, as well as the immune evasion strategies for chronic HCV infection.

Insights into antiviral innate immunity revealed by studying hepatitis C virus

Experimental studies on the interactions of the positive strand RNA virus hepatitis C virus (HCV) with the host have contributed to several discoveries in the field of antiviral innate immunity. These include revealing the antiviral sensing pathways that lead to the induction of type I interferon (IFN) during HCV infection and also the importance of type III IFNs in the antiviral immune response to HCV. These studies on HCV/host interactions have contributed to our overall understanding of viral sensing and viral evasion of the antiviral intracellular innate immune response. In this review, I will highlight how these studies of HCV/host interactions have led to new insights into antiviral innate immunity. Overall, I hope to emphasize that studying antiviral immunity in the context of virus infection is necessary to fully understand antiviral immunity and how it controls the outcome of viral infection.

IL28B gene polymorphisms in mono- and HIV-coinfected chronic hepatitis C patients

Introduction: Single-nucleotide polymorphisms (SNPs) associated with hepatitis C virus (HCV) clearance were identified near the IL28B gene. Coinfection by the human immunodeficiency virus (HIV) influences the course of HCV contributing to liver damage. Nevertheless, little is known about the relationship between these SNPs and HCV/HIV coinfection. Our aim was to estimate the frequencies of the allelic and genotypic variants of the IL28B polymorphisms rs12979860 (C/T) and rs8099917 (T/G) and their possible association with the establishment of HCV infection.

Methodology: A total of 199 non-infected controls and 230 patients with chronic hepatitis C, including 53 coinfected with HIV, participated in the study. Genotyping consisted of polymerase chain reaction and subsequent analysis of the restriction patterns resulting from exposure to endonucleases.

Results: Among the controls with established results, 47.4% (90/190) exhibited the rs12979860 CC genotype, 43.7 CT, and 8.9% TT, whereas 29.1% (66/227), 51.5%, and 19.4% of the patients exhibited the CC, CT, and TT genotypes, respectively. With respect to rs8099917, 66.8% (133/199) of the controls exhibited the TT genotype, 31.2% TG, and 2.0% GG, whereas 56.1% (129/230), 40.9%, and 3.0% of the patients exhibited the TT, TG, and GG genotypes, respectively.

Conclusion: The frequencies of the rs12979860 C allele and CC genotype and of the rs8099917 T allele and TT genotype were significantly higher among controls compared with patients, thus confirming the suggested protective effect against HCV infection. No significant difference was observed in the genotype and allelic distributions between the mono- and coinfected patients.