IL28B polymorphism associated with spontaneous clearance of hepatitis C infection in a Southern Brazilian HIV type 1 population

Like a Rolling Stone? A Review on Spontaneous Clearance of Hepatitis C Virus Infection

Elimination of hepatitis C virus (HCV) without the need for medical intervention, known as spontaneous clearance (SC), occurs at a significantly lower rate than in the case of hepatitis B virus infection and only in selected individuals, such as reportedly in Keith Richards, a guitarist of The Rolling Stones. The present paper provides an updated narrative review of the research devoted to the phenomenon in order to identify and discuss the demographic, lifestyle-related, clinical, viral genotype-related, and host genetic factors underpinning the SC occurrence. The body of evidence indicates that the likelihood of SC is decreased in older individuals, men, Black people, HIV-coinfected subjects, and intravenous drug and alcohol users. In turn, HBV coinfection and specific polymorphism of the genes encoding interferon lambda 3 (particularly at rs8099917) and interferon lambda 4 (particularly at rs12979860) and HLA genes increase the odds of SC. Numerous other host-specific genetic factors could be implicated in SC, but the evidence is limited only to certain ethnic groups and often does not account for confounding variables. SC of HCV infection is a complex process arising from a combination of various factors, though a genetic component may play a leading role in some cases. Understanding factors influencing the likelihood of this phenomenon justifies better surveillance of high-risk groups, decreasing health inequities in particular ethnic groups, and may guide the development of a prophylactic vaccine, which at present is not available, or novel therapeutic strategies. Further research is needed to elucidate the exact mechanisms underlying SC and to explore potential interventions that could enhance this natural antiviral response.

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.

Influence of IL28B and MxA gene polymorphisms on HCV clearance in Han Chinese population

The high rate of chronic hepatitis C (CHC) was one of the key issues of global public health concern. Interferon (IFN)-λ relevant genes were in the antiviral treatment pathway, not only influenced hepatitis C virus (HCV) spontaneous clearance, but also affected the IFN-mediated viral clearance. The aim of this study was to identify the association of interleukin 28B (IL28B), myxovirus resistance A (MxA) gene polymorphisms with HCV spontaneous clearance and therapeutic response in Chinese CHC patients. IL28B and MxA gene genotypes were detected among 231 CHC carriers, 428 subjects with HCV spontaneous clearance and 662 CHC patients with pegylated IFN-α and ribavirin (pegIFN-α/RBV) treatment. Patients with MxA rs2071430 TT genotype were more likely to develop HCV infection chronicity (additive model: odds ratio (OR) 1.22, 95% confidence interval (CI) 1.01-1.48, P = 0.042). IL28B rs1298075 variant genotypes (additive model: OR 0.58, 95% CI 0.34-0.98, P = 0.040) and MxA rs17000900 variant genotypes (additive model: OR 0.54, 95% CI 0.30-0.99, P = 0.048) were less likely to achieve a sustained virological response. The life table indicated that patients with IL28B rs1298075 AG genotype were slower to achieve a viral load 106 copies/ml (all P < 0.05). This study illustrated that the carriage of IL28B rs12980275 AA had a positive effect on treatment response to pegIFN-α/RBV among Chinese CHC patients.

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.

Profile of HIV subtypes in HIV/HBV- and HIV/HCV-coinfected patients in Southern Brazil

INTRODUCTION:

HIV and viral hepatitis infections are major causes of chronic disease worldwide and have some similarities with regard to routes of transmission, epidemiology, front barriers faced during access of treatment, and strategies for a global public health response. The objective was to describe the HIV-1 subtypes, viral tropism and single-nucleotide polymorphisms (SNPs) of interleukin 28B (IL28B) from a case series of HIV/viral hepatitis coinfected patients from southern Brazil.

METHODS:

Clinical and epidemiological data were evaluated by a review of medical records. Periodic blood draws were taken to determine the viral and host characteristics.

RESULTS:

This study included 38 patients with HIV/HBV or HIV/HCV coinfection; the median age was 49 years. Thirty-seven (97.4%) were on antiretroviral therapy, 32 (84.2%) had an undetectable viral load, a median CD4+ T-cell count of 452 cells/mm3. HIV-1 subtyping showed 47.4 and 31.6% of patients with subtypes C and B, respectively. Analysis of viral co-receptor usage showed a predominance of the R5 variant (64.7%), with no significant difference between the subtypes. Twenty patients with HIV/HCV coinfection were eligible to receive HCV therapy with pegylated-interferon-alpha plus ribavirin, and 10/20 (50%) of them achieved sustained virological response. SNPs of IL28B were evaluated in 93.3% of patients with HIV/HCV coinfection, and 17 (60.7%) presented the CC genotype.

CONCLUSIONS:

In the present case series, a higher frequency of HIV subtype C was found in coinfected patients. However such findings need to be prospectively evaluated with the inclusion of data from regional multicenter analyses.

Estimating the Time to Diagnosis and the Chance of Spontaneous Clearance During Acute Hepatitis C in Human Immunodeficiency Virus-Infected Individuals

BACKGROUND

Hepatitis C virus (HCV) infection is often asymptomatic, and the date of infection is almost impossible to determine. Furthermore, spontaneous clearance (SC) may occur, but little is known about its time of occurrence.

METHODS

Data on human immunodeficiency virus (HIV)-HCV coinfected individuals were used to inform a stochastic simulation model of HCV viral load kinetics, alanine aminotransferase (ALT), and HCV antibodies during acute hepatitis C. The dates of diagnosis and potential SC were estimated through a Bayesian approach. Hepatitis C virus diagnosis was assumed to be based on an elevated ALT level detected during a control visit for HIV-infected individuals, which occurred every 3 months (scenario A) or every 6 months (scenario B).

RESULTS

We found that HCV diagnosis occurred after a median of 115 days and 170 days of infection in scenarios A and B, respectively. Among spontaneous clearers, SC occurred after a median time of 184 days after infection. Seven percent (scenario B) to 10% (scenario A) of SCs appeared more than 6 months after diagnosis, and 3% (both scenarios) of SCs appeared more than 1 year after diagnosis.

CONCLUSIONS

Acute hepatitis C diagnosis occurs late in HIV-HCV coinfected individuals. Screening for HCV in HIV-infected individuals should be performed frequently to reduce delays. Our findings about late occurrence of SC support "wait and see" strategies for treatment initiation from an individual basis. However, early treatment initiation may reduce HCV transmission.

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.

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.

Hepatitis C virus infection in patients with HIV-1: epidemiology, natural history and management

Hepatitis C virus (HCV)-related liver diseases have contributed to increased morbidity and mortality in HIV-1-infected individuals in the era of effective antiretroviral therapy. HCV transmission patterns have changed among the HIV co-infected population during the last decade, with acute HCV infection emerging worldwide. HIV infection accelerates the progression of HCV-related liver diseases and consequently cirrhosis, liver failure, and hepatocellular carcinoma. However, the current standard treatment of HCV infection with pegylated interferon plus ribavirin results in only a limited viral response. Furthermore, cumbersome pill regimens, antiretroviral related hepatotoxicity, and drug interactions of HCV and HIV regimens complicate therapy strategies. Fortunately, in the near future, new direct-acting anti-HCV agents will widen therapeutic options for HCV/HIV co-infection. Liver transplantation is also gradually accepted as a therapeutic option for end stage liver disease of HCV/HIV co-infected patients.

SNP rs8099917 in gene IL28B might be associated with risk of chronic infection by HCV but not with response to treatment

AIM

The aim of this study was to characterize the genetic profile of patients with chronic hepatitis C virus (HCV) infection relative to polymorphisms rs12979860 and rs8099917 in gene IL28B and the association of those polymorphisms with the response to treatment with pegylated interferon and ribavirin, performed at a reference center in Brazilian Amazonia.

METHODS

A total of 75 individuals with chronic hepatitis C and 98 healthy individuals from both genders over 18 years old were assessed. DNA samples were collected from leukocytes and subjected to real-time polymerase chain reaction to genotype polymorphisms rs12979860 and rs8099917.

RESULTS

Analysis of the allelic and genotypic frequencies of the investigated polymorphisms showed that both groups were in Hardy-Weinberg equilibrium; polymorphism rs12979860 exhibited no significant difference between the groups. For polymorphism rs8099917, allele T was significantly less frequent (P = 0.0195) among the patients (63.3%) than the controls (75.5%), and the patients were 1.7 times as likely to exhibit allele G. No difference in response to treatment was associated with SNP patterns.

CONCLUSION

The results suggest a possible association of SNP rs8099917 with higher odds of chronic HCV infection but do not indicate a putative influence of the investigated SNPs on the sustained virologic response.

Alcohol misuse and illicit drug use are associated with HCV/HIV co-infection

We studied hepatitis C virus (HCV) prevalence and risk factors for HCV infection in a sample of Brazilian HIV-positive patients. A cross-sectional study was conducted with 580 HIV-positive patients from a specialized HIV/AIDS diagnosis and treatment centre in southern Brazil. All patients were interviewed for socio-demographic and risk factors and tested for HCV antibodies and HCV-RNA detection. A multivariate analysis was performed to identify risk factors for HCV infection. A total of 138 (24%) patients had past or chronic hepatitis C. The following risk factors were associated with HCV infection for each gender: alcohol misuse and injecting drug use in women (P < 0·001) and low educational level, smoking drug use, and injecting drug use in men (P < 0·01). These results suggest that alcohol misuse, low educational level, smoking drug use, and injecting drug use are probable risk factors for HCV infection in HIV-positive patients. This information contributes to an understanding of the epidemiology of HIV/HCV co-infection in Brazil.

Interleukin 28B-related polymorphisms: a pathway for understanding hepatitis C virus infection?

AIM

To analyze the role of rs12979860 and rs8099917 polymorphisms in hepatitis C virus (HCV) genotype 1 infection of Brazilians.

METHODS

A total of 145 adult patients diagnosed with genotype 1 chronic hepatitis C (CHC) who had completed a 48-wk regimen of pegylated-interferon α-2a or -2b plus ribavirin combination therapy were recruited from six large urban healthcare centers and 199 healthy blood donors (controls) from a single site between January 2010 and January 2012. Data on the patients' response to treatment was collected. Polymerase chain reaction-restriction fragment length polymorphism genotyping of the interleukin (IL)28B gene fragment encompassing the single nucleotide polymorphisms (SNPs) rs12979860 (C/T) and rs8099917 (T/G) was carried out for 79 of the CHC patients and 199 of the controls. Bi-directional amplicon sequencing of the two SNPs was carried out for the remaining 66 CHC patients.

RESULTS

SNP rs12979860 genotyping was successful in 99.5% of the controls and 97.2% of the CHC patients, whereas the SNP rs8099917 genotyping was successful in 95.5% of the controls and 100% of the CHC patients. The genotype and allele distributions for both rs12979860 and rs8099917 were significantly different between the control and CHC patient groups, with significantly higher genotype frequencies of CC and TT in the controls (P = 0.037 and 0.046, respectively) and of TT and GG in the CHC patients (P = 0.0009 and 0.0001, respectively). Analysis of the CHC patients who achieved sustained virological response (SVR) to treatment (n = 55) indicated that the rs12979860 C allele and CC genotype were predictors of SVR (P = 0.02). No significant correlation was found between rs8099917 genotypes and treatment response, but carriers of the T allele showed significantly higher rates of SVR (P = 0.02). Linkage disequilibrium analysis of the group that achieved SVR showed a significant association between rs12979860 and rs8099917 (P = 0.07).

CONCLUSION

The higher allele frequency of rs12979860 C and rs8099917 T observed in non-HCV-infected individuals may indicate a potential protective role for these IL28B-related polymorphisms.

Prevalence and risk factors of Hepatitis C virus infection in Brazil, 2005 through 2009: a cross-sectional study

BACKGROUND

Hepatitis C chronic liver disease is a major cause of liver transplant in developed countries. This article reports the first nationwide population-based survey conducted to estimate the seroprevalence of HCV antibodies and associated risk factors in the urban population of Brazil.

METHODS

The cross sectional study was conducted in all Brazilian macro-regions from 2005 to 2009, as a stratified multistage cluster sample of 19,503 inhabitants aged between 10 and 69 years, representing individuals living in all 26 State capitals and the Federal District. Hepatitis C antibodies were detected by a third-generation enzyme immunoassay. Seropositive individuals were retested by Polymerase Chain Reaction and genotyped. Adjusted prevalence was estimated by macro-regions. Potential risk factors associated with HCV infection were assessed by calculating the crude and adjusted odds ratios, 95% confidence intervals (95% CI) and p values. Population attributable risk was estimated for multiple factors using a case-control approach.

RESULTS

The overall weighted prevalence of hepatitis C antibodies was 1.38% (95% CI: 1.12%-1.64%). Prevalence of infection increased in older groups but was similar for both sexes. The multivariate model showed the following to be predictors of HCV infection: age, injected drug use (OR = 6.65), sniffed drug use (OR = 2.59), hospitalization (OR = 1.90), groups socially deprived by the lack of sewage disposal (OR = 2.53), and injection with glass syringe (OR = 1.52, with a borderline p value). The genotypes 1 (subtypes 1a, 1b), 2b and 3a were identified. The estimated population attributable risk for the ensemble of risk factors was 40%. Approximately 1.3 million individuals would be expected to be anti-HCV-positive in the country.

CONCLUSIONS

The large estimated absolute numbers of infected individuals reveals the burden of the disease in the near future, giving rise to costs for the health care system and society at large. The known risk factors explain less than 50% of the infected cases, limiting the prevention strategies. Our findings regarding risk behaviors associated with HCV infection showed that there is still room for improving strategies for reducing transmission among drug users and nosocomial infection, as well as a need for specific prevention and control strategies targeting individuals living in poverty.

A single nucleotide polymorphism, rs129679860, in the IL28B locus is associated with the viral kinetics and a sustained virological response in a chronic, monoinfected hepatitis C virus genotype-1 Brazilian population treated with pegylated interferon-ribavirin

Single nucleotide polymorphisms (SNPs) in the interleukin (IL)28B locus have been associated with a sustained virological response (SVR) in interferon-ribavirin (IFN-RBV)-treated chronic hepatitis C virus (HCV)-infected patients in European and African populations. In this study, the genotype frequency of two IL28B SNPs (rs129679860 and rs8099917) in a cohort of chronic HCV-monoinfected patients in Brazil was evaluated and the SNP sufficient to predict the treatment response outcome was determined. A total of 66 naïve genotype-1 chronic HCV-infected patients were genotyped and the associated viral kinetics and SVR were assessed. The overall SVR was 38%. Both the viral kinetics and SVR were associated with rs129679860 genotypes (CC = 62% vs. CT = 33% vs. TT = 18%, p = 0.016). However, rs8099917 genotypes were only associated with SVR (TT = 53% vs. TG = 33% vs. GG = 18%; p = 0.032). In this population, the analysis of a single SNP, rs12979860, successfully predicts SVR in the IFN-RBV treatment of HCV.

Test of IL28B polymorphisms in chronic hepatitis C patients treated with PegIFN and ribavirin depends on HCV genotypes: results from a meta-analysis

BACKGROUND

Many studies have been published on the association between single nucleotide polymorphisms (SNP) near the IL28B gene and response to the combined treatments of pegylated-interferon (PegIFN) and ribavirin (RBV) in chronic HCV-infected patients, but without identical conclusions. The aim of this study was to assess impact of the IL28B polymorphisms on the effect of HCV standard treatment using meta-analysis based method.

METHODS

Association studies between polymorphisms of rs12979860 or rs8099917 and response to PegIFN/RBV treatment in chronic HCV patients were retrieved from PubMed. Data of qualified studies on sustained virological response (SVR) in different genotypes were extracted and analyzed using meta-analysis method in Stata 10 software.

RESULTS

Thirty-four papers, containing 46 independent studies, were included in the analysis. In the HCV G1/4 patients without treatment history, individuals carrying rs12979860 CC genotype were more likely to achieve SVR (OR 3.97, 95%CI 3.29-4.80) compared to those carrying CT/TT genotypes. Similar results were observed in the HCV G1/4 patients with unsuccessful or unknown treatment history (OR 3.76, 95%CI 2.67-5.28) or in the patients co-infected with human immunodeficiency virus (OR 5.20, 95%CI 3.04-8.90). However, associations could not be observed in HCV G2/3 patients. For rs8099917, similar results were obtained for genotype TT compared to genotypes TG/GG, indicating that TT genotype was significantly associated with better treatment response in patients infected with genotype 1 or 4 HCV, but not genotype 2 or 3 HCV.

CONCLUSION

Polymorphisms of rs12979860 and rs8099917 near IL28B only associate with the treatment response to PegIFN/RBV in patients infected with HCV genotype 1 or 4 but not with genotype 2 or 3, irrespective of the previous treatment history or HIV co-infected status. Therefore, identification of IL28B genotypes is necessary only in patients infected with relatively difficult-to-treat genotype 1 or 4 HCV.

Lack of TGF-β production by hepatitis C virus-specific T cells during HCV acute phase is associated with HCV clearance in HIV coinfection

BACKGROUND & AIMS

Immunity and genetic factors govern the recovery from acute hepatitis C virus (HCV) infection. No predictive factors have been yet identified in patients coinfected with the human immunodeficiency virus (HIV). We investigated whether early T cell responses to HCV producing transforming-growth-factor beta (TGF-β) predict the outcome of acute HCV coinfection, independently of the IL-28B gene polymorphism.

METHODS

Intracellular cytokine staining assays against HCV-core, E1, NS2, and NS4 overlapping peptides were used for the analysis of peripheral HCV-specific TGF-β-producing T cells. Patients were genotyped for IL-28B polymorphisms. Healthy donors' samples were tested as controls. Twenty-four acute hepatitis C-HIV+ patients were followed-up for 15 months defining two groups: (A) Recovered (n=16, 5 spontaneous recoveries, 11 sustained virologic response after treatment), (B) Chronic HCV (n=8, 4 spontaneous chronic course, 4 therapeutic failures).

RESULTS

During the acute pretreatment phase, core/NS2-specific TGF-β-producing CD4+ and/or CD8+ T cells were detected in 8/24 (33%) patients. Lack of anti-HCV TGF-β+ cells was characteristic of healthy donors and Group A, except for 2 cases, with frequencies significantly lower than in Group B (p=0.04 and 0.01), and was associated with recovery in 14/16 cases. Presence of anti-HCV TGF-β+ cells was associated with persistent viremia in 6/8 cases (p=0.005). This profile remained stable over time. Such TGF-β production was independent of the rs129679860 SNP (p=1.0) which was not associated with recovery (p=1.0).

CONCLUSIONS

During acute hepatitis C, pre-therapeutic HCV-specific TGF-β-producing T cells are a new marker independent of the IL-28B gene polymorphism, predicting the lack of spontaneous or therapeutic HCV clearance.

Genetics of IL28B and HCV--response to infection and treatment

The IL28B locus attracted the attention of HCV researchers after a series of genome-wide association studies independently identified a strong association between common IL28B polymorphisms and the outcome of PEG-IFN-α plus ribavirin combination therapy in patients chronically infected with HCV genotype 1. This association was subsequently replicated for other HCV genotypes and has been linked to spontaneous eradication of HCV, development of steatosis and biochemical changes (such as altered levels of γ-glutamyl transpeptidase and LDL). Despite the introduction of direct-acting antiviral drugs, IL28B genetics are likely to play a part in patient selection and treatment decisions-moving towards a personalized approach to therapy. In HCV-infected patients with the so-called favourable IL28B genotype (rs12979860 CC; associated with better treatment response), hepatic expression levels of IL28B and interferon-stimulated genes seem to be reduced at baseline, but are induced more strongly after IFN-α administration, perhaps resulting in more effective elimination of the virus. Clarification of the mechanisms underlying these biological phenomena will lead to improved understanding of the antiviral effects of IFN-λ and, ideally, to the development of better therapies against HCV infection. This Review summarizes current understanding of the role of IL28B in HCV infection and response to therapy.