Polymorphisms of interferon-λ4 and IL28B - effects on treatment response to interferon/ribavirin in patients with chronic hepatitis C

A Role of Variance in Interferon Genes to Disease Severity in COVID-19 Patients

The rapid rise and global consequences of the novel coronavirus disease 19 (COVID-19) have again brought the focus of the scientific community on the possible host factors involved in patient response and outcome to exposure to the virus. The disease severity remains highly unpredictable, and individuals with none of the aforementioned risk factors may still develop severe COVID-19. It was shown that genotype-related factors like an ABO Blood Group affect COVID-19 severity, and the risk of infection with SARS-CoV-2 was higher for patients with blood type A and lower for patients with blood type O. Currently it is not clear which specific genes are associated with COVID-19 severity. The comparative analysis of COVID-19 and other viral infections allows us to predict that the variants within the interferon pathway genes may serve as markers of the magnitude of immune response to specific pathogens. In particular, various members of Class III interferons (lambda) are reviewed in detail.

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.

Value of IFNL3 genetic polymorphism in the prediction of HCV treatment response to direct-acting antiviral drugs versus interferon therapy

Background: Despite the outstanding results of direct-acting antiviral therapies (DAAs) of Hepatitis C infection (HCV), non-responders had to be more defined. Aim: assess the outcome of DAAs in linkage with Interferon lambda 3 (IFNL3) in HCV patients. Methods: This case-control-study was conducted on 495 chronic-HCV (genotype-4a), previously treated Egyptians by either DAAs (responders 195, 120 relapsers) or interferon/ribavirin (IFN/RBV) (140 responders, 60 relapsers), and 98 healthy controls. IFNL3 distribution, clinical and laboratory data were assessed. Results: CT was the most predominant genotype in Egyptians (51%). All genotypes were sensitive to DAAs mainly CT genotype (60%), even TT genotype (resistant to IFN/RBV 40%) had 29.2% sensitivity. CT genotype was predominant in sofosbuvir/Daclatasvir responders (67.6%) (OR = 0.66), while non-CT prevailed in relapsers (56.7%). TT genotype may respond to SOF/Ledi better than other regimens (66.7%). In IFN/RBV relapsers; CT genotype was commoner (50%) than others, while CC genotype predominated in responders (54.3%). The c allele was the commonest in responders to IFN/RBV (71.4%), while the T allele was resistant to treatment (65% in relapsers). Addition of RBV to SOF/DCV reported higher resistance with CT genotype (42.2%-50%) and TT genotype (17.8%-27.8%). Conclusion: This study recommended IFNL3 genotyping to be a prerequisite before stratifying treatment for HCV-4a Egyptians.

Hierarchical assessment of host factors influencing the spontaneous resolution of hepatitis C infection

BACKGROUND

Hepatitis C virus (HCV) infection is associated with chronic liver disease, resulting in cirrhosis and hepatocellular carcinoma. Approximately 20% of HCV infections are spontaneously resolved. Here, we assessed the hierarchical relevance of host factors contributing to viral clearance.

METHODS

DNA samples from 40 resolved infections and 40 chronic HCV patients paired by age were analyzed. Bivariate analysis was performed to rank the importance of each contributing factor in spontaneous HCV clearance.

RESULTS

Interestingly, 63.6% of patients with resolved infections exhibited the protective genotype CC for SNP rs12979860. Additionally, 59.3% of patients with resolved infections displayed the protective genotype TT/TT for SNP ss469415590. Moreover, a ranking of clearance factors was estimated. In order of importance, the IL28B CC genotype (OR 0.197, 95% CI 0.072-0.541) followed by the INFL4 TT/TT genotype (OR 0.237, 95% CI 0.083-0.679), and female gender (OR 0.394, 95% CI 0.159-0.977) were the main predictors for clearance of HCV infection.

CONCLUSIONS

HCV clearance is multifactorial and the contributing factors display a hierarchical order. Identifying all elements playing role in HCV clearance is of the most importance for HCV-related disease management. Dissecting the relevance of each contributing factor will certainly improve our understanding of the pathogenesis of HCV infection.

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.

Pharmacogenetics and the treatment of HIV-/HCV-coinfected patients

This review will summarize the role of pharmacogenetics in the natural history of hepatitis C, particularly in patients with HIV/HCV and will take the perspective of pharmacogenetics and its influence on the response to antiviral therapy and the susceptibility to develop adverse effects. This review will also devote a section to host genetics in other clinical situations, such as disease progression and acute HCV infection, which may determine whether treatment of HIV-/HCV-coinfected patients is implemented or deferred.

Association of IL-28B, TBX21 gene polymorphisms and predictors of virological response for chronic hepatitis C

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. The outcomes of both spontaneous HCV clearance and response to therapy depend on both viral and host factors. To investigate the influence of polymorphisms of IL-28B rs12979860 and TBX21 rs17250932, rs4794067 as well as viral factors (HCV genotype, F protein) on the outcome of HCV infection, we genotyped 565 patients with chronic HCV infection, 191 patients spontaneously resolved from HCV infection, 359 healthy controls and 383 treatment-naïve CHC patients with pegylated interferon-α and ribavirin (PEG IFN-α/RBV). Results showed that TBX21 rs4794067 variant genotypes significantly correlated with increased risk of HCV chronic infection (dominant model: OR = 5.690, 95% CI = 2.024-16.000) and susceptibility (dominant model: OR = 5.658, 95% CI = 2.514-12.735). We also found that the rs12979860, rs2227982 and rs36084323 polymorphisms showed no significant associations with susceptibility or spontaneous clearance of HCV in the anti-F antibody subgroup; however, the anti-F antibody positive subgroup might show an increased risk of N-SVR (all P < 0.001). Our results demonstrate that variant factors in both the host and pathogen are commonly important for HCV clearance. In addition rs4794067 and F protein status may be strong predictive markers in the Chinese population.

The evaluation of interferon lambda 4 rs368234815 as a predictor factor in treated patients with chronic hepatitis C genotype 1a infection

CONTEXT

Host factors including single-nucleotide polymorphisms (SNPs) in or near interferon lambda (IFNL) gene are the important factors in predicting response to treatment of chronic hepatitis C (CHC).

AIMS

The aim of this study was to determine the frequency and association of IFNL4 rs368234815 with IFNL3 SNPs rs12979860, rs8099917 and other factors including cholesterol, alanine aminotransferase, fibrosis, viral load, age and body mass index in genotype 1a treated CHC patients, to achieve rapid virologic response (RVR) and sustained virologic response (SVR).

SUBJECTS AND METHODS

A total of 71 hepatitis C virus genotype 1a patients were enrolled from 2013 to 2015. The genotypes of rs12979860, rs8099917 were identified by polymerase chain reaction (PCR) and restriction fragment length polymorphism while the genotype rs368234815 detected by amplification-refractory mutation system-PCR.

RESULTS

The rate of RVR and SVR were 43/71 (60.6%) and 46/71 (64.8%), respectively. To achieve an SVR in patients with rs368234815, TT/TT genotype 20/24 (83.3%) was found to be higher than other SNPs. The correlation coefficient of rs368234815 was strongly associated with rs12979860 (r = 0.788, P < 0.001). Multivariate logistic regression showed that the cholesterol (odds ratio [OR]: 0.205, confidence interval [CI] 95%: 0.047-0.891, P = 0.035), age (OR: 0.160, CI 95%: 0.035-0.730, P = 0.018), baseline viral load (OR: 0.167, CI 95%: 0.032-879, P < 0.035) and IFNL4 (OR: 5.453, CI 95%: 1.015-29.293, P < 0.048) could be independent predictors of SVR.

CONCLUSIONS

The results of these findings emphasise that factors such as age, cholesterol, baseline viral load and IFNL4 rs368234815 are better predictive factors and should be evaluated before CHC treatment.

IFNL4 rs368234815 and rs117648444 variants predict off-treatment HBsAg seroclearance in IFN-treated HBeAg-negative chronic hepatitis B patients

BACKGROUND & AIM

Robust baseline predictors of interferon (IFN) response in HBeAg-negative chronic hepatitis B (CHB) patients are not currently available. The recently described rs368234815 TT/ΔG dinucleotide and rs117648444 nonsynonymous P70S polymorphisms in IFN lambda 4 (IFNL4) gene, which are strongly associated with response to IFN in hepatitis C virus (HCV) infection, could be also useful in IFN-treated CHB patients. Here we assessed whether IFNL4 rs368234815 and rs117648444 polymorphisms predict IFN-induced HBsAg clearance in CHB patients.

METHODS

We sequenced the IFNL4 gene on genomic DNA collected from 126 HBeAg-negative CHB patients treated with IFN and followed up for a median of 11 (1-23) years.

RESULTS

The 15-year cumulative probability of HBsAg loss in the 62 carriers of the rs368234815 TT/TT genotype, which abolishes the IFNλ4 protein production, was comparable to that of 19 patients carrying the rs117648444 T allele predicted to produce an impaired IFNλ4-S70 protein (39% vs 42%, P  =  .827). In contrast, these 81 patients, either not producing IFNλ4 or producing an impaired IFNλ4-S70 protein, had a significantly higher 15-year probability of HBsAg loss compared to the 45 subjects predicted to encode only the fully functional IFNλ4-P70 (42% vs 11% P = .003). At multivariate analysis, combination of the rs368234815 and rs117648444 genotypes strongly predicted HBsAg clearance (HR 5.90, 95% CI 1.70-20.9, P = .006) together with pretreatment serum HBV DNA levels (HR 0.57, 95% CI 0.39-0.83, P = .003).

CONCLUSION

IFNL4 rs368234815 and rs117648444 functional variants are worth to be investigated as pretreatment combined predictors of IFN response in HBeAg-negative CHB patients.

Neonatal Exposure to Hepatitis C Virus Antigens in Uninfected Children Born to Infected Mothers

OBJECTIVE

Vertical transmission of hepatitis C virus (HCV) infection is uncommon and occurs in approximately 5% of births from HCV-infected mothers. The reason for the low transmission rate is unclear. We aimed to investigate whether there is evidence of HCV exposure also in the noninfected children born to HCV-infected mothers by the presence of a detectable immune response.

METHODS

Serum and peripheral blood mononuclear cells from 9 HCV vertically infected children, 32 uninfected children born to HCV infected mothers, and 15 HCV chronically infected mothers, were analyzed. HCV-RNA-negative adults and children were used as controls. HCV-specific T cell responses were analyzed by interferon gamma using an enzyme-linked immunospot assay and 3H-thymidine incorporation assay. HCV antibodies were also analyzed.

RESULTS

An HCV-specific T cell response was detected in 73% (11/15) of the HCV-infected mothers, 67% (6/9) of the vertically infected children, 56% (18/32) of the exposed but uninfected children and in 10% and 20% of the control groups, respectively. The 2 groups of HCV-exposed children both had a significantly higher proportion of HCV-specific T cell responders compared to pediatric controls (P = 0.01 and P = 0.02).

CONCLUSIONS

HCV-specific immune responses were more common in children born to HCV-infected mothers, regardless of the presence of HCV RNA. We conclude that noninfected children born to HCV-infected mothers may have been exposed to HCV antigens.

The impact of genetic variation in IL28B, IFNL4 and HLA genes on treatment responses against chronic hepatitis C virus infection

Single nucleotide polymorphisms (SNPs) near the interleukin-28B (IL28B), interferon lambda 4 (IFNL4) and the human leukocyte antigen (HLA) gene are associated with treatment responses in patients with chronic hepatitis C (CHC) virus infection treated with pegylated interferon-α and ribavirin (pegIFN-α/RBV). We compared the role of IL28B SNPs (rs12979860, rs12980275, and rs8099917), IFNL4 ss469415590 and HLA rs4273729 with treatment outcomes in patients with CHC virus. A total of 520 Iranian patients with CHC infection were enrolled. SNPs in IL28B, IFNL4 ss469415590 and HLA rs4273729 were genotyped by PCR-restriction fragment length polymorphism, TaqMan® Real-Time PCR and direct sequence. Out of 520 CHC treatment-naive patients, 42.9% were infected with HCV-1a, 15.4% with HCV-1b, 9.8% with HCV-2, and 31.9% with HCV-3a. Rapid virologic response (RVR), complete early virologic response (cEVR), and sustained virologic response (SVR) were 53.3%, 73.8%, and 66.7%, respectively. Multivariate logistic regression analysis showed that IL28B rs12980275 and IFNL4 ss469415590 in all HCV genotypes were associated with RVR. In addition, IL28B rs12979860 and RVR in all HCV genotypes and IL28B rs12980275, IFNL4 ss469415590, and HLA rs4273729 in HCV subtypes 1a, 1b, and 3a correlated with cEVR. In patient's achieving-SVR, IL28B rs12980275, and RVR in all HCV genotypes and IL28B rs12979860, IFNL4 ss469415590, and HLA rs4273729 in HCV subtypes 1a, 1b, and 3a were the powerful predictor factors. As the first report of its kind published in Iran, we indicated that beside IL28B SNPs and HLA rs4273729, IFNL4 ss469415590 was a powerful predictor factor for RVR, cEVR and SVR. Genotyping these SNPs may be a helpful priority in the treatment of patients with HCV infection, especially in countries where access to triple or double therapy with a viral protease inhibitor is limited.

Genetic variants in interferon-λ 4 influences HCV clearance in Chinese Han population

Recent many studies indicated a novel dinucleotide variant in ss469415590 (TT vs. ΔG) of interferon-λ 4 (IFNL4) gene strongly associated with hepatitis C virus clearance. To evaluate the impact and clinical usefulness of IFNL4 ss469415590 genotype on predicting both spontaneous HCV clearance and response to therapy in Chinese population, we genotyped 795 chronic HCV carriers, 460 subjects with HCV natural clearance and 362 patients with pegylated interferon-α and ribavirin (PEG IFN-α/RBV) treatment. IFNL4 ss469415590 variant genotypes significantly decreased host HCV clearance, both spontaneous (dominant model: OR = 0.50, 95% CI = 0.36-0.71) and IFN-α induced (dominant model: OR = 0.32, 95% CI = 0.18-0.56). Multivariate stepwise analysis indicated that ss469415590, rs12979860, the level of baseline HCV RNA and platelet were as independent predictors for sustained virological response (SVR). But the area under the ROC curve (AUC) was only 0.58 for ss469415590, and it was elevated to 0.71 by adding rs12979860, baseline HCV RNA and platelet in the prediction model of SVR. Therefore, these findings underscore that although genetic factors of host and pathogen were commonly important during HCV clearance, ss469415590 may be also a strongly predictive marker in the Chinese population.

IL28B genotyping and treatment of HCV infected subjects

Background: Chronic hepatitis C is a common cause of advanced liver disease and appropriate treatment has been complex and a challenge. Reaction of individual genotypes to classical pegylated interferon-ribavirin therapy differs and no success has been achieved in some even after repeated therapy cycles. New types of so called directly acting antivirals (DAAs) are hopeful, as shown in many recent clinical studies, and triple therapy regimens involving DAA are becoming the new standard of care.

Objective: To summarize knowledge about the relationship between HCV therapeutic regimens and the genetic background of the host represented by interleukin 28B (IL28B) gene polymorphisms. In the first part, the host basic mechanisms in specific and innate immunity are introduced. The IL28B genotype and its role in the course of HCV treatment are described in the second part.

Methods: We searched and summarized publications on HCV therapeutic regimens and host IL28B polymorphisms.

Results: Compared to classical regimens, the association between IL28B polymorphism and treatment outcome of HCV infected patients is weaker in triple therapy using first generation DAAs boceprevir and telaprevir.

Conclusions: The association between IL28B polymorphism and treatment outcome is lessened with availability of new therapeutic regimens. Nevertheless, IL28B genotyping may still be useful for individualization of treatment strategies.

A Simple PCR-RFLP Method for Genotyping of IFNL4 rs368234815 Polymorphism in Patients With Chronic Hepatitis C

BACKGROUND

The IFNL4 rs368234815 polymorphism plays a prominent role in spontaneous and treatment-induced clearance of hepatitis C virus (HCV) infection. This study aimed to develop a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for assessment of rs368234815 polymorphism.

METHODS

We genotyped the rs368234815 polymorphism in 87 patients with chronic HCV by PCR sequencing and PCR-RFLP methods, simultaneously.

RESULTS

Genotyping of IFNL4 rs368234815 via PCR-RFLP was concordant with PCR sequencing in all 87 individuals (100%). The analytical sensitivity and specificity of the developed PCR-RFLP method for genotyping of rs368234815 polymorphism were each 100%. Among these patients with chronic HCV, the frequency of rs368234815 TT/TT, TT/ΔG, and ΔG/ΔG were 44.8%, 37.9%, and 17.3%, respectively.

CONCLUSIONS

The PCR-RFLP method that we developed is accurate, rapid, inexpensive, and easy to perform for genotyping of the IFNL4 rs368234815 polymorphism. This method can be used for clinical and research work.

Hepatitis C Viral Kinetic Changes in a Retrospective Cohort Study of Chronic Hepatitis C Virus Egyptian Patients on Pegylated Interferon and Ribavirin Therapy

The aim of this study was to determine the relative importance of the kinetics of antiviral response compared to baseline host and virological factors for predicting treatment outcome. A retrospective analysis of 285 chronic hepatitis C virus (HCV) patients, encompassing genotypes 4 treated with peginterferon alpha-2a and ribavirin, was performed. Baseline characteristics were compared across HCV genotypes and pretreatment factors associated with rapid virological response (RVR) were identified. The relative significance of RVR compared to other baseline factors for predicting sustained virological response was analyzed by multiple logistic regression analysis. Ninety-seven percent of the patients harbored HCV genotype 4a patients. The positive predictive value (PPV) of RVR for end-of-treatment response (ETR) was 88% and of early virological response (EVR) was 85%, which means that achievement of both RVR and EVR is a good positive predictive factor of response. The negative predictive value (NPV) of RVR for ETR was low and equals 26.77%, which means that approximately two-thirds of patients were able to achieve ETR despite not experiencing RVR, which means RVR is a bad negative predictive factor of response. The NPV of EVR for ETR was high and equals 90%, which means that only 10% of patients were able to achieve an ETR despite not experiencing EVR, which explains that EVR is a very good negative predictive factor of response. In univariate logistic regression analysis, which included the following: female gender, alanine aminotransferase, aspartate transaminase, α-fetoprotein, baseline HCV-RNA levels, grade of activity, stage of fibrosis, and positive HCV-RNA, by polymerase chain reaction at week 4, none of the previous factors was a significant independent factor of failure of response to treatment. The current study demonstrated that a viremia at week 4 has a good PPV, but it has a very low NPV. The NPV of EVR was more robust for ETR (90%). EVR is regarded as a robust indicator of treatment outcome, and a 12-week stopping rule for patients is strongly evident.

Correlation of interferon-lambda 4 ss469415590 with the hepatitis C virus treatment response and its comparison with interleukin 28b polymorphisms in predicting a sustained virological response: a meta-analysis

BACKGROUND

Interferon-lambda 4 (IFNL4) ss469415590 is a newly discovered polymorphism that could predict the treatment response in hepatitis C virus (HCV)-infected patients. This meta-analysis was performed in order to clarify its specific effect on the treatment response and to compare it with interleukin 28b (IL28B).

METHOD

The commonly used literature databases were searched. Meta-analyses were performed with fixed/random-effects models using Stata 12.0. The sustained virological response (SVR) rate was summarized using R software. Publication bias was examined through Egger's test.

RESULTS

A total of seven studies were finally included in this meta-analysis. IFNL4 ss469415590 was demonstrated to be associated with SVR (odds ratio (OR) 3.83, 95% confidence interval (CI) 3.22-4.56, p<0.001). Asians had a higher likelihood of achieving SVR than Caucasians (OR=7.36 vs. 3.54). When stratifying all the patients according to HCV genotype, a significant association was observed in HCV genotype 1 patients (OR 4.5, 95% CI 2.91-6.95, p<0.001). In HCV genotype 2/3 patients, the favorable TT/TT genotype patients tended to have a statistically higher SVR rate than the non-TT/TT genotype patients (84.4% vs. 78.3%, p=0.058). Compared with IL28B rs12979860 (OR 3.45) and rs8099917 (OR 3.50), ss469415590 TT/TT genotype patients showed a slightly higher probability of achieving a SVR (OR 3.61 calculated from studies investigating both IFNL4 and rs12979860; OR 4.86 for studies investigating both IFNL4 and rs8099917). Furthermore, ss469415590 showed a slightly higher predictive value than rs12979860 using the diagnostic test tool (area under the curve=0.71 vs. 0.70). IFNL4 was also correlated with rapid virological response (RVR) (OR 4.35, 95% CI 1.43-13.20, p=0.01), viral clearance (OR 0.31, 95% CI 0.24-0.39, p<0.001), and HCV susceptibility (OR 0.76, 95% CI 0.65-0.89, p=0.001).

CONCLUSIONS

IFNL4 ss469415590 is significantly associated with SVR in HCV genotype 1 patients, irrespective of race; there is a tendency towards an association in HCV genotype 2/3 patients. Comparable to IL28B, IFNL4 is correlated with natural viral clearance and HCV susceptibility, additionally IFNL4 ss469415590 has a slightly higher predictive performance over IL28B polymorphisms in regard to SVR.

Interleukin-10.rs1800896 and Interleukin-18.rs1946518 gene polymorphisms could not predict the outcome of hepatitis C virus infection in Egyptian patients treated with pegylated interferon plus ribavirin

A single-nucleotide polymorphism (SNP) in the interleukin (IL)-28B gene was used as a major predictor of the response to treatment in patients with hepatitis C virus (HCV) infection. Data examining the role of IL-10 and IL-18 gene polymorphisms among HCV genotype 4 (G4)-infected Egyptians in response to pegylated interferon (PEG-IFN) plus ribavirin (RBV) therapy are limited. This study investigated the impact of SNP at IL-10.rs1800896 (at position -1082) and IL-18.rs1946518 genes (at position -607) on the response to PEG-IFN/RBV therapy in HCV-infected Egyptians. This study was carried out on 100 HCV patients treated with PEG-IFN plus RBV and 100 healthy controls. The HCV patients included 50 treatment non-responders (NR) and 50 subjects with sustained virologic response (SVR). Genomic DNA from venous blood of subjects was extracted and IL-10.rs1800896 and IL-18.rs1946518 genotypes were determined using allele-specific amplification and SYBR Green real-time PCR. Linkage disequilibrium between the two SNPs was estimated using Haploview software. The frequency of the IL-10.rs1800896 AA, AG and GG genotypes among non-responders were 16 %, 70 % and 14 % while among SVR subjects, the frequency was 34 %, 60 % and 6 %, respectively (p=0.073). On the other hand, the frequency of the IL-18.rs1946518 AA, AC and CC genotypes among non-responders was 14 %, 50 % and 36 %, respectively, while among responders, these frequencies were 28 %, 44 % and 28 %, (p = 0.220). Both markers were in linkage equilibrium (D' = 0.23; r (2) = 0.052). SNPs in the IL-10.rs1800896 and IL-18.rs1946518 genes could not predict the outcome of HCV infection in Egyptians treated with PEG-IFN/RBV.

The interferon lambda 4 rs368234815 predicts treatment response to pegylated-interferon alpha and ribavirin in hemophilic patients with chronic hepatitis C

Background:

A dinucleotide variant rs368234815 in interferon lambda 4 (IFNL4) gene was recently found to be associated with the hepatitis C virus (HCV) treatment response. This study aimed to assess the impact of IFNL4 rs368234815 polymorphism on treatment response to pegylated-IFN alpha (Peg-IFN-α) and ribavirin (RBV) in hemophilic patients with chronic hepatitis C (CHC).

Materials and Methods:

In this retrospective study, 92 hemophilic patients with CHC who were treated with Peg-IFN-α/RBV were investigated. Single-nucleotide polymorphisms (SNPs) in IFNL genomic region including rs368234815, rs12979860, and rs8099917 were analyzed by DNA sequencing.

Results:

Of the 92 patients, 63 (68.5%) achieved sustained virological response (SVR). Of the 43 patients with rs368234815 TT/TT genotype, 36 (83.7%) achieved SVR, while in 49 patients with non-TT/TT genotypes, 27 (55.1%) achieved SVR. Other pretreatment parameters predicted SVR were patients’ body mass index, HCV genotype, rs12979860, and rs8099917 SNPs. In multivariate analysis, all above-mentioned parameters except rs8099917 remained as predictors of SVR. IFNL4 rs368234815 was a strong predictor of SVR; however, the prediction power of this SNP was the same as that of rs12979860 SNP in the patients of the current study.

Conclusion:

IFNL4 rs368234815 SNP can be considered for decision-making in the treatment of HCV-infected patients.

HCV eradication does not impact gut dysbiosis or systemic inflammation in cirrhotic patients

BACKGROUND

Eradication of hepatitis C virus (HCV) is increasing but its residual impact on the pro-inflammatory milieu in cirrhosis, which is associated with gut dysbiosis, is unclear.

AIM

To define the impact of sustained virological response (SVR) on gut dysbiosis and systemic inflammation in HCV cirrhosis patients.

METHODS

Cirrhotic out-patients with HCV with/without SVR (achieved >1 year prior) and age-matched healthy controls underwent serum and stool collection. Serum was analysed for IL-6, TNF-α and endotoxin while stool microbiota analysis was performed using multitagged pyrosequencing. Microbial comparisons were made using UNIFRAC and cirrhosis dysbiosis ratio (lower score indicates dysbiosis). Comparisons were performed between cirrhotics with/without SVR and controls vs. cirrhotic patients.

RESULTS

A total of 105 HCV cirrhotics and 45 age-matched healthy controls were enrolled. Twenty-one patients had achieved SVR using pegylated interferon + ribavrin a median of 15 months prior. No significant differences on demographics, cirrhosis severity, concomitant medications or diabetes were seen between cirrhotics with/without SVR. There was no significant difference in overall microbiota composition (UNIFRAC P = 0.3) overall or within specific microbial families (cirrhosis dysbiosis ratio median 1.3 vs. 1.0, P = 0.45) between groups with/without SVR. This also extended towards IL-6, TNF-α and endotoxin levels. Both cirrhosis groups, however, had significant dysbiosis compared to healthy controls [UNIFRAC P = 0.01, cirrhosis dysbiosis ratio (1.1 vs. 2.9, P < 0.001)] along with higher levels of endotoxin, IL-6 and TNF-α.

CONCLUSIONS

Gut dysbiosis and a pro-inflammatory systemic milieu, are found in HCV cirrhosis regardless of SVR. This persistent dysbiosis could contribute towards varying rates of improvement after HCV eradication in cirrhosis.

Interferon lambda 4 (IFNL4) gene polymorphism is associated with spontaneous clearance of HCV in HIV-1 positive patients

Approximately one-third of the individuals infected with human immunodeficiency virus type 1 (HIV-1) are co-infected with hepatitis C virus (HCV). Co-infected patients have an increased risk for developing end-stage liver diseases. Variants upstream of the IFNL3 gene have been associated with spontaneous and treatment-induced clearance of HCV infection. Recently, a novel polymorphism was discovered, denoted IFNL4 ΔG > TT (rs368234815), which seems to be a better predictor of spontaneous clearance than the IFNL4 rs12979860 polymorphism. We aimed to determine the prevalence of the IFNL4 ΔG > TT variants and to evaluate the association with spontaneous clearance of HCV infection in Brazilian HIV-1 patients. The IFNL4 ΔG > TT genotypes were analyzed by polymerase chain reaction followed by restriction digestion in 138 HIV-1 positive patients who had an anti-HCV positive result. Spontaneous clearance of HCV was observed in 34 individuals (24.6%). IFNL4 genotype distribution was significantly different between individuals who had spontaneous clearance and chronic HCV patients (p=0.002). The probability of spontaneous clearance of HCV infection for patients with the IFNL4 TT/TT genotype was 3.6 times higher than for patients carrying the IFNL4 ΔG allele (OR=3.63, 95% CI:1.51-8.89, p=0.001). The IFNL4 ΔG > TT polymorphism seems to be better than IFNL4 rs12979860 to predict spontaneous clearance of the HCV in Brazilian HIV-1 positive patients.

Population Polymorphism of IFNL3 and IFNL4 Genes of Type 3 Interferon Associated with Spontaneous Clearance of Hepatitis C Virus in Representatives of Caucasian and Mongoloid Races

The frequency of single nucleotide polymorphisms of IFNL3 gene (rsl12979860 and rs8099917) and dinucleotide polymorphism of IFNL4 gene (ss469415590) were estimated in healthy inhabitants of Mongolia and Irkutsk regions taking into account their races. Population and genetic studies were performed in 1520 conventionally healthy volunteers (blood donors), representatives of Caucasian and Mongoloid races. Significant race-related differences in the incidence of IFNL3 and IFNL4 gene polymorphisms associated with spontaneous clearance of hepatitis C virus were found in healthy volunteers.

Association between IFNL4 rs368234815 polymorphism and sustained virological response in chronic hepatitis C patients undergoing PEGylated interferon/ribavirin therapy: A meta-analysis

BACKGROUND AND AIMS

Many studies have been published on the association between IFNL4 rs368234815 single-nucleotide polymorphism (SNP) and sustained virological response (SVR) in chronic hepatitis C (CHC) patients undergoing treatment with PEGylated interferon (PEG-IFN) plus ribavirin (RBV). Because of the variable and sometimes inconsistent results, we performed a meta-analysis to estimate the association between these factors.

METHODS

We conducted a search of the literature published prior to July 1, 2014. The pooled results were analyzed as the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) using random-effect model.

RESULTS

The pooled results revealed that the rs368234815 TT/TT genotype was significantly correlated with SVR in HCV-1/4-infected Caucasian patients (OR=4.65, 95% CI=3.36-6.42, P<0.00001) but not in HCV-2/3-infected Caucasian patients (OR=1.44, 95% CI: 0.89-2.33, P=0.13). Conversely, the rs368234815 ΔG/ΔG genotype was significantly linked to treatment failure in Caucasian patients (OR=0.49, 95% CI: 0.38-0.64, P<0.00001), regardless of the HCV genotype.

CONCLUSION

The results of the meta-analysis suggest that IFNL4 rs368234815 polymorphism may be a predictor of SVR in Caucasian HCV-1/4-infected patients.

IFNL4 ss469415590 polymorphism contributes to treatment decisions in patients with chronic hepatitis C virus genotype 1b, but not 2a, infection

Recently, the dinucleotide variant ss469415590 (TT/ΔG) in a novel gene, interferon lambda 4 (IFNL4), was identified as a stronger predictor of hepatitis C virus (HCV) clearance in individuals of African ancestry compared with rs12979860. We aimed to determine whether this variant contributes to treatment decisions in a Chinese population. A total of 447 chronic hepatitis C (CHC) patients (including 328 treated with interferon alpha-2b and ribavirin), 129 individuals who had spontaneously cleared HCV (SHC), and 169 healthy controls were retrospectively investigated. ss469415590 genotyping was performed using a mass spectrometry method (SEQUENOM). A higher proportion of SHC individuals carried the TT/TT genotype compared with CHC patients (95.3% vs. 88.8%, P=0.027). In patients with HCV genotype 1b, the ss469415590 variant was independently associated with sustained virologic response (SVR) (odds ratio [OR]=3.247, 95% confidence interval [CI]=1.038-10.159, P=0.043) and on-treatment virological responses, including rapid (RVR), complete early (cEVR), early (EVR), and end-of-treatment (ETVR), with a minimal OR of 3.73. Especially for patients with high viral load (≥4×10(5) IU/ml), ΔG allele carriers had a lower chance of achieving SVR compared with those carrying the TT/TT genotype (7.1% vs. 36.0%, P=0.034, OR [95% CI]=7.24 [1.02-318.45], negative predictive value=92.9%). In patients with HCV genotype 2a, no significant association between the ss154949590 variant and the virological response was identified (P>0.05). Additionally, we found that ss154949590 was in complete linkage disequilibrium with rs12979860. In conclusion, the IFNL4 ss154949590 TT/TT genotype favors spontaneous clearance of HCV. This same variant is associated with treatment-induced clearance in patients with genotype 1b, but not 2a. ss469415590 (or rs12979860) genotyping should be considered for patients with HCV genotype 1b and high viral load when making a choice between standard dual therapy and an IFN-free direct-acting antiviral regimen.

Interferon Lambda 4 Polymorphism Predicts Sustained Viral Response in Hepatitis C Virus Patients Irrespective of Hepatitis C Virus Genotypes, Ethnicity or Treatment Regimen: Results From a Meta-Analysis

CONTEXT

There is growing evidence that interferon lambda 4 (IFNL4) polymorphism is related to sustained virological response (SVR) in hepatitis C virus (HCV) infection. We analyzed the relationship between IFNL4 (rs368234815) polymorphism and SVR in dual- and triple- therapy in HCV genotype 1, 2, 3 and 4 infected Asian, Caucasian and African patients.

EVIDENCE ACQUISITION

We performed a systematic search of PubMed, Medline, Embase, EBSCO and Web of Science databases up to July 2015. Data of qualified studies were analyzed using the meta-analysis method in Stata 12.0 software.

RESULTS

Ten studies involving 4765 patients were included in the analysis. Of overall studies, SVR was more frequent in TT/TT genotype compared to TT /ΔG+ΔG /ΔG (OR = 4.439, 95% CI: 3.410 - 5.778). Genotype stratification analyses revealed rs368234815 TT/ TT was associated with higher SVR in G1, G2/3 and G4 HCV patients (ORG1 = 4.661, 95% CI: 3.937 - 5.518; ORG2/3 = 1.896, 95% CI: 1.265 - 2.841; ORG4 = 6.074; 95% CI: 3.129 - 11.788). Ethnicity stratification analyses of G1 patients showed that SVR was more frequent with TT/ TT genotype in Asians (OR= 8.245, 95% CI: 5.475 - 12.416), Caucasians (OR = 4.166, 95% CI: 3.441 - 5.042) and Africans (SVR: 37.5% vs 17.0%, P = 0.017). Moreover, similar results presented in therapy stratification analyses both in patients with dual-therapy (OR = 3.857; 95% CI: 3.288 - 4.524) or triple-therapy (OR = 8.119; 95% CI: 4.942 - 13.340).

CONCLUSIONS

Favorable IFNL4 rs368234815 genotype is a strong predictor of SVR in HCV patients, irrespective of HCV genotypes, ethnicity or treatment regimen. Thus, detection for IFNL4 rs368234815 polymorphism may be beneficial to guide the clinician in the individualization of therapy and design.

Hepatitis C genotype 4: The past, present, and future

Hepatitis C virus (HCV) genotype (GT) 4 represents 12%-15% (15-18 million) of total global HCV infection. It is prevalent in Northern and Equatorial Africa and the Middle East, and is also present in some countries in Europe. GT-4 (and subtype 4a in particular) dominates the HCV epidemic in Egypt. In underdeveloped countries, risk factors associated with HCV infection may be due to unsafe medical practices or other factors such as familial transmission, mother’s HCV status, or illiteracy. HCV prevention and control programs should include health education, increased community awareness towards the disease, controlling infection distribution in health-care centers, proper sterilization of medical and dental instruments, and ensuring safe supply of blood and blood-products. Response rates to a 48-wk combined pegylated-interferon (PEG-IFN) and ribavirin (RBV) treatment range from 40%-69%, and HCV-GT-4 has been considered better than GT-1 but worse than GT-2 and GT-3 in treatment with PEG-IFN/RBV. However, with the introduction of the HCV-GT-1 effective protease inhibitors boceprevir and telaprevir in 2011, HCV-GT-4 became the “most difficult (GT) to treat”. Recently, the direct-acting antivirals (DAAs) with pan- genotypic activities simeprevir, sofosbuvir, and daclatasvir have been recommended in triple regimens with PEG-IFN/RBV for the treatment of HCV-GT-4. An IFN-free regimen will be available for treatment of all genotypes of HCV in the near future. To date, several DAAs have been developed and are currently being evaluated in various combinations in clinical trials. As new regimens and new agents are being approved by the Food and Drug Administration, we can expect the guidelines for HCV treatment to be changed. The availability of shorter, simpler, and more tolerable treatment regimens can reduce the morbidity and mortality associated with HCV infection. With such a large number of therapeutic agents available, we can end up with a range of choices that we can select from to treat patients.

Immunopathogenesis of Hepatitis C Virus Infection

Despite advances in therapy, hepatitis C virus infection remains a major global health issue with 3 to 4 million incident cases and 170 million prevalent chronic infections. Complex, partially understood, host-virus interactions determine whether an acute infection with hepatitis C resolves, as occurs in approximately 30% of cases, or generates a persistent hepatic infection, as occurs in the remainder. Once chronic infection is established, the velocity of hepatocyte injury and resultant fibrosis is significantly modulated by immunologic as well as environmental factors. Immunomodulation has been the backbone of antiviral therapy despite poor understanding of its mechanism of action.

Comparison of Three Different Methods for Detection of IL28 rs12979860 Polymorphisms as a Predictor of Treatment Outcome in Patients with Hepatitis C Virus

Objectives

This study aimed to evaluate the specificity, sensitivity, cost, and turn-around time of three methods of gene polymorphism analysis and to study the relationship between IL28B rs12979860 and SVR rate to pegIFN-α/RVB therapy among patients with chronic hepatitis C.

Methods

A total of 100 samples from chronic hepatitis C patients were analyzed in parallel using the three methods: direct sequencing, real-time polymerase chain reaction (PCR), amplification refractory mutation system (ARMS)-PCR.

Results

The different profiles for IL28B rs12979860 alleles (CC, CT, and TT) obtained with PCR-RFLP, ARMS-PCR, and direct sequencing were consistent among the three methods. Prevalence of rs12979860 genotypes CC, CT and TT in HCV genotype 1a was 10(19.6%), 35(68.6%), and six (11.8%), respectively, and in HCV genotype 31, it was 13(26.5%), 31(63.3%), and five (10.2%), respectively. No significant difference was seen between rs12979860 genotype and HCV genotype (p = 0.710).

Conclusion

Screening by ARMS – PCR SNOP detection represents the most efficient and reliable method to determine HCV polymorphisms in routine clinical practice.

Effect of IL28B genotype on hepatitis B and C virus infection

Genetic factors play a major role for treatment response and disease progression of chronic hepatitis B (HBV) and C virus (HCV) infection. In 2009 a genome-wide association study (GWAS) identified a single nucleotide polymorphism near the IL28B gene that was associated with treatment-induced viral clearance in chronic HCV infection treated with pegylated interferon-α (PEG-IFN) and ribavirin (RBV). Further, another GWAS found an association between IL28B genotype and spontaneous viral clearance in acute HCV infection. The effect on sustained viral response (SVR) could also be observed in patients receiving a triple-therapy with a direct antiviral agent (DAA) combined with PEG-IFN/RBV. In the era of all-oral interferon-free treatment regimens with the combination of different DAAs-with SVR rates exceeding 90%-the effect of IL28B was blunt. In contrast, in HBV several retrospective studies yielded conflicting results of the association of IL28B with PEG-IFN-induced treatment response.

IFN-λ gene polymorphisms as predictive factors in chronic hepatitis C treatment-naive patients without access to protease inhibitors

The single nucleotides polymorphisms analyses in the regions near the IL28B gene in patients chronically infected with genotype 1 hepatitis C virus (HCV) are an important predictive factor for sustained virological response (SVR). The aim was to assess the predictive value of the polymorphisms of the IL28B/IFNL3 gene in patients chronically infected with genotype 1 for the viral clearance obtained after initial treatment including admixed populations. A systematic review was conducted, using a meta-analysis in the PubMed, Embase, LILACS, and SCIELO using MesH and DECS in 42 studies. The parameters were IL28B polymorphisms, rs12979860, rs8099917, and rs12980275, SVR ratio, and OR (odds ratio). OR and confidence Interval of 95% (95%CI), were calculated by fixed or random effects models. Heterogeneity, sensitivity analysis, and publication bias were also performed. Significant differences were noted between carriers groups with the major versus minor allele at rs12979860 CC versus CT/TT-genotype (OR = 4.18; 95%CI = 3.37-5.17), rs8099917 TT versus TG/GG-genotype (OR = 4.07; 95%CI = 2.94-5.63), and rs12980275 AA versus AA/AG-genotype (OR = 5.34; 95%CI = 1.60-17.82). There was selection bias in the rs8099917 analysis (Egger's regression P = 0.049), which reversed after performing a sensitivity analysis (P = 0.510). The incorporation of SNP analyses in IL28B/IFNL3 gene during the diagnosis process in Brazil should be used as a complementary tool to determine the appropriate treatment for HCV genotype 1. Here, we confirm that the rs12979860 CC, rs8099917 TT, and rs12980275 AA genotype-carriers have favorable responses to standard therapy, including two studies with Brazilian population, and this information should be considered.

IL28B rs12980275 variant as a predictor of sustained virologic response to pegylated-interferon and ribavirin in chronic hepatitis C patients: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The IL-28B rs12979860 CC and rs8099917 TT genotypes were proved to be predictor for pegylated-interferon (PEG-IFN)/ribavirin (RBV)-treated hepatitis C virus (HCV) patients. However, there were no identical conclusions on rs12980275 polymorphism. Our aim is to perform a meta-analysis in order to determine the association between rs12980275 polymorphism of IL28B and the sustain viral response (SVR) of HCV patients with PEG-IFN/RBV therapy.

METHODS

Studies were retrieved from PubMed and Chinese China National Knowledge Infrastructure (CNKI). Data were extracted by two investigators and analyzed using Stata 11.0 software.

RESULTS

Sixteen articles, containing 19 independent studies were included in the analysis. The results showed that patients with AA genotype of rs12980275 achieved higher SVR than patients with AG/GG genotypes. The overall OR (95% CI) was 3.118 (2.146, 4.529). In subgroup analysis by ethnicity, the ORs (95% CIs) were 3.084 (1.454, 6.542) and 2.736 (1.863, 4.018) in Asian and Caucasian population, respectively. Another subgroup analysis by HCV genotype, the ORs (95% CIs) were 3.976 (2.568, 6.158), 1.462 (0.504, 4.240) and 1.489 (0.916, 2.421) in patients with HCV genotype 1/4, mix genotype, and HCV genotype 2/3, respectively.

CONCLUSION

AA genotype of rs12980275 was a predictive factor for SVR in HCV patients with PEG-IFN/RBV treatment, especially in HCV genotype 1/4.

The correlation between hepatitis C core antigen and hepatitis C virus RNA levels with respect to human immunodeficiency virus status, hepatitis C virus genotype and interferon-lambda-4 polymorphism

OBJECTIVES

Serum hepatitis C virus (HCV) core antigen (HCVcAg) concentrations correlate with HCV RNA levels in HCV monoinfected patients. Data in HCV/HIV coinfected patients are still limited. We aim to compare the use of HCVcAg measurement with respect to HIV status, HCV genotypes, interferon-lambda-4 (IFNL4) polymorphism and clinical parameters.

METHODS

We analyzed an untreated cohort of 104 patients with HCV monoinfection and 85 patients with HCV/HIV coinfection. Serum HCVcAg was measured by a commercial chemiluminescent microparticle immunoassay. The presence of IFNL4 polymorphism ss469415590 was identified by real-time PCR.

RESULTS

log10 HCVcAg levels were significantly correlated with corresponding log10 HCV RNA levels (r = 0.889, p < 0.001), but not with ALT levels and liver stiffness. The correlation between HCV RNA and HCVcAg was particularly high in coinfected patients and those with high viremia. Mean log10 HCVcAg concentration was significantly higher in coinfected patients than in monoinfected patients. Patients harboring the TT/TT genotype of ss469415590 had significantly higher levels of log10 HCVcAg than those with the non-TT/TT genotype. HCVcAg levels were similar across HCV genotypes.

CONCLUSIONS

HCVcAg concentrations had an excellent correlation with HCV RNA levels, particularly in HCV/HIV-coinfected individuals and might be associated with IFNL4 polymorphism. HCVcAg testing could be used as an alternative to HCV RNA assays in resource-limited settings.

The Role of Interferon-λ Locus Polymorphisms in Hepatitis C and Other Infectious Diseases

Since its discovery in 2003, the type III interferon-λ (IFN-λ) family has been found to contribute significantly to the host response to infection. Whilst IFN-λ shares many features with type I IFN induction and signalling pathways, the tissue-specific restricted expression of its receptor, IL28RA, makes IFN-λ a major mediator of host innate immunity in tissues and organs with a high epithelial cell content. Host susceptibility and responses to infection are known to be heterogeneous, and the identification of common genetic variants linked to disease outcome by genome-wide association studies (GWAS) has underscored the significance of host polymorphisms in responses to infection. Several such GWAS have highlighted the IFN-λ locus on chromosome 19q13 as an area of genetic variation significantly associated with hepatitis C virus (HCV) infection, and the rs12979860 genotype can be used in clinical practice as a biomarker for predicting a successful response to treatment with pegylated IFN and ribavarin. Here, we discuss IFN-λ genetic polymorphisms and their role in HCV and other infectious diseases as well as their potential impact on clinical diagnostics, patient stratification and therapy. Finally, the broader role of IFN-λ in the immunopathogenesis of non-infectious inflammatory diseases is considered.

Hepatitis C virus and interferon type III (interferon-λ3/interleukin-28B and interferon-λ4): genetic basis of susceptibility to infection and response to antiviral treatment

There has been a significant increase in our understanding of the host genetic determinants of susceptibility to viral infections in recent years. Recently, two single-nucleotide polymorphisms (SNPs), rs12979860 T/C and rs8099917 T/G, upstream of the interleukin (IL)-28B/interferon (IFN)-λ3 gene have been clearly associated with spontaneous and treatment-induced viral clearance in hepatitis C virus (HCV) infection. Because of their power in predicting the response to IFN/ribavirin therapy, the above SNPs have been used as a diagnostic tool, even though their relevance in the management of HCV infection will be blunt in the era of IFN-free regimens. The recent discovery of a new genetic variant, ss469415590 TT/ΔG, upstream of the IL-28B gene, which generates the novel IFN-λ4 protein, has opened up a new and alternative scenario to understand the functional architecture of type III IFN genomic regions and to improve our knowledge of the pathogenetic mechanism of HCV infection. A role of ss469415590 in predicting responsiveness to antiviral therapy has also been observed in HCV-infected patients receiving direct antiviral agents. The underlying biological mechanism that links the above IL-28B polymorphisms (in both IFN-λ3 and IFN-λ4) to spontaneous and treatment-induced clearance of HCV infection remains to be discovered. Despite this, shedding some light on this issue, which is the main aim of this review, may provide new insights into the general topic of 'host genetics and viral infections'.

Predictive value of interferon-lambda gene polymorphisms for treatment response in chronic hepatitis C

BACKGROUND

IL28B gene polymorphism is the best baseline predictor of response to interferon alfa-based antiviral therapies in chronic hepatitis C. Recently, a new IFN-L4 polymorphism was identified as first potential functional variant for induction of IL28B expression. Individualization of interferon alfa-based therapies based on a combination of IL28B/IFN-L4 polymorphisms may help to optimize virologic outcome and economic resources.

METHODS

Optimization of treatment outcome prediction was assessed by combination of different IL28B and IFN-L4 polymorphisms in patients with chronic HCV genotype 1 (n = 385), 2/3 (n = 267), and 4 (n = 220) infection treated with pegylated interferon alfa (PEG-IFN) and ribavirin with (n = 79) or without telaprevir. Healthy people from Germany (n = 283) and Egypt (n = 96) served as controls.

RESULTS

Frequencies of beneficial IL28B rs12979860 C/C genotypes were lower in HCV genotype 1/4 infected patients in comparison to controls (20-35% vs. 46-47%) this was also true for ss469415590 TT/TT (20-35% vs. 45-47%). Single interferon-lambda SNPs (rs12979860, rs8099917, ss469415590) correlated with sustained virologic response (SVR) in genotype 1, 3, and 4 infected patients while no association was observed for genotype 2. Interestingly, in genotype 3 infected patients, best SVR prediction was based on IFN-L4 genotype. Prediction of SVR with high accuracy (71-96%) was possible in genotype 1, 2, 3 and 4 infected patients who received PEG-IFN/ribavirin combination therapy by selection of beneficial IL28B rs12979860 C/C and/or ss469415590 TT/TT genotypes (p<0.001). For triple therapy with first generation protease inhibitors (PIs) (boceprevir, telaprevir) prediction of high SVR (90%) rates was based on the presence of at least one beneficial genotype of the 3 IFN-lambda SNPs.

CONCLUSION

IFN-L4 seems to be the best single predictor of SVR in genotype 3 infected patients. For optimized prediction of SVR by treatment with dual combination or first generation PI triple therapies, grouping of interferon-lambda haplotypes may be helpful with positive predictive values of 71-96%.

IL28B polymorphism cannot predict response to interferon alpha treatment in patients with melanoma

BACKGROUND

Recent genome-wide association studies revealed the rs12979860 single nucleotide polymorphism (SNP) of the IL28B gene (CC genotype) to be the strongest pre-therapeutic predictor of therapy response to interferon alpha in patients with chronic hepatitis C infection. The favorable CC genotype is associated with significantly higher rates of sustained virologic response. No data exist on the role of IL28B polymorphism in interferon therapy of diseases other than viral hepatitis.

METHODS

A retrospective study involving 106 patients with melanoma who received low- or high-dose interferon therapy was performed. The CC and non-CC genotype of IL28B rs12979860 SNP were correlated with progression-free and overall survival.

RESULTS

44 (41.5%) patients were CC and 62 (58.5%) non-CC. There was no statistically significant difference in age at diagnosis, melanoma type or localization, Breslow level or AJCC stage between CC and non-CC patients. During the observation period (6.43±4.66 years) disease progression occurred in 36 (34%) patients after 5.5±4.3 years. 43.2% (19) of patients with CC and 27.4% (17) of patients with non-CC genotype were affected (p = 0.091). Disease progression was more frequent in patients on high dose interferon therapy and with a worse AJCC stage.

CONCLUSION

In contrast to classical risk factors like tumor thickness and clinical stage, IL28B polymorphism was not associated with progression-free or overall survival in patients with melanoma treated with interferon alpha.

Impact of a single nucleotide polymorphism upstream of the IL28B gene in patients positive for anti-HCV antibody in an HCV hyperendemic area in Japan

The influence of genetic variation at the interleukin-28B (IL28B) locus on the natural course of hepatitis C virus (HCV) infection has not been fully investigated. The goal of this study was to examine whether an IL28B polymorphism (rs8099917) is associated with natural clearance of HCV and with disease parameters of HCV infection in an HCV hyperendemic area of Japan. The patients were 502 anti-HCV antibody-positive residents who participated in liver disease screening program from 2002 to 2004. Patients who underwent interferon-based therapy or had hepatocellular carcinoma were excluded. Of these patients, 149 were negative for HCV RNA (prior infection) and 353 were positive for HCV RNA or HCV core antigen (HCV carriers). In multivariate analysis, the IL28B TT genotype was a predictor for prior HCV infection. In addition, nine of the patients with prior HCV infection were positive for anti-HCV antibody with positive for HCV core antigen or HCV RNA before 2001, and these nine patients all had the IL28B TT genotype. Furthermore, the IL28B TT genotype was associated independently with higher HCV core antigen levels in HCV carriers. In contrast, the IL28B genotype did not affect the biochemical markers, such as alanine aminotransferase, hepatic fibrosis markers, and α-fetoprotein, and the degree of hepatic fibrosis assessed by transient elastography in HCV carriers. We concluded that IL28B polymorphism (TT genotype) is associated with spontaneous clearance of HCV and conversely with high viral loads in HCV carriers. In contrast, the IL28B genotype does not affect disease progression such as hepatic fibrosis.

IFNL4 polymorphism predicts response to hepatitis C treatment after liver transplantation

BACKGROUND

Recent studies in chronic hepatitis C patients have shown that rs368234815 polymorphism nearby IL28B is a better predictor of response to antiviral treatment with pegylated interferon and ribavirin than IL28B polymorphisms (rs12979860 and rs8099917). Its effect could be related to interferon lambda 4 (IFNL4), a protein which seems to confer some paradoxical disadvantages in hepatitis C virus (HCV) immune response.

OBJECTIVES

To assess the role of IFNL4 rs368234815 polymorphism on the response to antiviral treatment after liver transplantation (LT).

STUDY DESIGN

IFNL4 and IL28B polymorphisms were genotyped in 86 HCV-infected LT recipients and in their donors; all patients had undergone antiviral treatment with pegylated interferon and ribavirin after LT.

RESULTS

IFNL4 polymorphism strongly correlated with IL28B ones (p < 0.001). The favorable IFNL4 genotype (TT/TT) was significantly more frequent among donors than recipients (60% donors vs. 22% recipients, p <0.001). Recipient TT/TT genotype was associated with a higher sustained virological response rate after LT (p = 0.024). Nevertheless, the highest sustained virological response frequency was found when both donors and recipients had favorable genotypes (73% vs. 25%, p = 0.002), suggesting a role for donor genotype.

CONCLUSIONS

Our study demonstrates that IFNL4 rs368234815 polymorphism is an important predictor of response to antiviral treatment in the LT setting. These findings warrant further studies on IFNL4 role in immune response against HCV.

The Impact of IFNL4 rs12979860 Polymorphism on Spontaneous Clearance of Hepatitis C; A Case-Control Study

BACKGROUND

About 30% of individuals with hepatitis C virus (HCV) infection are able to clear HCV spontaneously. Differences in host genetics affect the outcome of HCV infection. Single nucleotide polymorphisms (SNPs) of the Interferon lambda (IFNL) genes were associated with spontaneous and treatment-induced clearance of HCV infection.

OBJECTIVES

The aim of this study was to evaluate the association between the IFNL4 rs12979860 SNP and spontaneous clearance of HCV infection in Iranian population.

MATERIALS AND METHODS

A case-control study was designed on 91 cases with spontaneous HCV infection clearance and 259 patients with persistent HCV infection as the control group. The rs12979860 SNP was assessed as the most common IFNL polymorphism by PCR-RFLP method.

RESULTS

Distribution of rs12979860 CC genotype in the spontaneous clearance group was around two folds of its distribution in chronic hepatitis C group (P < 0.001, OR = 4.09, 95% CI = 2.44-6.86).

CONCLUSIONS

The rs12979860 SNP was observed as a strong host genetic factor associated with spontaneous clearance of hepatitis C infection.

Pharmacogenetics of hepatitis C: transition from interferon-based therapies to direct-acting antiviral agents

Hepatitis C virus (HCV) has emerged as a major viral pandemic over the past two decades, infecting 170 million individuals, which equates to approximately 3% of the world’s population. The prevalence of HCV varies according to geographic region, being highest in developing countries such as Egypt. HCV has a high tendency to induce chronic progressive liver damage in the form of hepatic fibrosis, cirrhosis, or liver cancer. To date, there is no vaccine against HCV infection. Combination therapy comprising PEGylated interferon-alpha and ribavirin has been the standard of care for patients with chronic hepatitis C for more than a decade. However, many patients still do not respond to therapy or develop adverse events. Recently, direct antiviral agents such as protease inhibitors, polymerase inhibitors, or NS5A inhibitors have been used to augment PEGylated interferon and ribavirin, resulting in better efficacy, better tolerance, and a shorter treatment duration. However, most clinical trials have focused on assessing the efficacy and safety of direct antiviral agents in patients with genotype 1, and the response of other HCV genotypes has not been elucidated. Moreover, the prohibitive costs of such triple therapies will limit their use in patients in developing countries where most of the HCV infection exists. Understanding the host and viral factors associated with viral clearance is necessary for individualizing therapy to maximize sustained virologic response rates, prevent progression to liver disease, and increase the overall benefits of therapy with respect to its costs. Genome wide studies have shown significant associations between a set of polymorphisms in the region of the interleukin-28B (IL28B) gene and natural clearance of HCV infection or after PEGylated interferon-alpha and ribavirin treatment with and without direct antiviral agents. This paper synthesizes the recent advances in the pharmacogenetics of HCV infection in the era of triple therapies.

Review article: genetic factors that modify the outcome of viral hepatitis

BACKGROUND

Genetic factors can play an important role for treatment response and disease progression in chronic viral hepatitis.

AIM

To review the influence of host genetic factors on the clinical course as well as on treatment response in patients with viral hepatitis.

METHODS

Review of the literature.

RESULTS

A landmark genome-wide association study (GWAS) identified polymorphisms in the IL28B gene on chromosome 19 (19q13.13) associated with response to therapy with pegylated interferon-α (PEG-IFN) and ribavirin (RBV) and spontaneous viral clearance in acute hepatitis C. Furthermore, IL28B genotype is associated with changes of lipid metabolism and insulin resistance. A further GWAS demonstrated that ITPA genetic variants protect HCV genotype 1 patients from RBV-induced anaemia. Another polymorphism in the patatin-like phospholipase domain containing 3 (PNPLA3) is associated with hepatic steatosis. Difficult-to-treat hepatitis C patients homozygous for GG had an up to five-fold lower chance of viral clearance on PEG/RBV than non-GG patients. In chronic hepatitis B patients treated with PEG-IFN several retrospective analyses of IL28B rs12980275 and rs12979860 genotypes yielded conflicting results which can be explained by the heterogeneity between the study populations. Some variants of the HLA-DP locus (HLA-DPA1 A allele and HLA-DPB1) protect against progression of chronic hepatitis B infection.

CONCLUSIONS

The determination of IL28B polymorphisms may be useful to individualise treatment options when using PEG/RBV based therapies for chronic hepatitis C infection. In contrast, so far identified genetic factors play only a minor role in chronic hepatitis B infection.

IFNL4 ss469415590 variant shows similar performance to rs12979860 as predictor of response to treatment against Hepatitis C Virus genotype 1 or 4 in Caucasians

Objectives

The rs12979860 variant, linked to IL28B gene, predicts sustained viral response (SVR) to pegylated-interferon/ribavirin (pegIFN/RBV) therapy in Hepatitis C Virus genotype 1 or 4 (HCV-1/4)-infected patients. Recently, a functional variant, ss469415590, in linkage disequilibrium (LD) with rs12979860, has been discovered. Our objective was to assess the value of ss469415590 to predict SVR to pegIFN/RBV in Caucasian HCV-1/4-infected individuals and to compare its performance with that of rs12979860.

Methods

272 Caucasian HCV-1/4-infected patients who completed a course of pegIFN/RBV were genotyped for both rs12979860 and ss469415590 markers. Logistic regression models including factors with univariate association with SVR and each genetic marker were elaborated. The area under the receiver operating-characteristic curve (AUROC) was calculated for each model and both were compared.

Results

Both markers were in LD (r² = 0.82). For rs12979860, 66 (64.0%) CC versus 56 (33.1%) T allele carriers achieved SVR (Adjusted OR = 4.156, 95%CI = 2.388–7.232, p = 4.647×10⁻⁷). For ss469415590, 66 (66.0%) TT/TT versus 56 (32.5%) –G allele carriers (Adjusted OR = 4.783, 95%CI = 2.714–8.428, p = 6.153×10⁻⁸) achieved SVR. The AUROC of the model including rs12979860 was 0.742 (95%CI = 0.672–0.813) and of that based on ss469415590 was 0.756 (95%CI = 0.687–0.826) (p = 0.780).

Conclusions

The ss469415590 variant shows an equivalent performance to predict SVR to pegIFN/RBV than the rs2979860 in Caucasian HCV-1/4-infected patients.

IL28B polymorphisms and clinical implications for hepatitis C virus infection in Uzbekistan

AIMS

Genome-wide association studies highlighted single nucleotide polymorphisms (SNPs) within the IFNL3/IL28B locus predict the treatment outcome for patients with HCV. Furthermore, SNPs in newly discovered IFNL4 are shown to have population-specific correlation with spontaneous clearance of HCV. The aim of this study was to examine the prevalence and clinical significance of the outlined SNPs in a population from Central Asia, a multi-ethnic region with a developing economy and a high prevalence of HCV infection.

METHODS

One hundred and thirty-five chronic HCV patients from Uzbekistan were enrolled. DNA specimens were extracted from peripheral blood mononuclear cells and the IFNL3 SNPs (rs8099917, rs12979860) were genotyped by the Invader Plus assay, the TaqMan assay, and by direct sequence analysis. The IFL4 region (ss469415590) was sequenced.

RESULTS

Of the 135 patients that completed 24 or 48 weeks of treatment with Peg-IFN-α plus RBV, 87.4% were of Central Asian (CA) ancestry and 12.6% were of Eastern European (EE) ancestry. A non-virological response was observed in 21.2% of CA and in 35.3% of EE, respectively (p<0.32). The rs12979860 was strongly associated with treatment response (OR, 5.2; 95% CI, 1.9-14.6; p<0.004) in the overall sample; however, SNP rs8099917 was the most predictive of outcome for CA group (OR, 6.9; 95% CI, 2.6-18.0; p<0.002). The allele frequency of IFNL4 SNP, ss469415590, was identical with that of rs12979860 in all samples.

CONCLUSIONS

SNPs in IFNL3 and IFNL4 can be used to predict HCV treatment outcome in a population of Central Asian ancestry.