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A polymorphism in IL28B distinguishes exposed, uninfected individuals from spontaneous resolvers of HCV infection.

ABSTRACT: BACKGROUND & AIMS:Polymorphisms in the interleukin-28B (IL28B) gene are associated with outcomes from infection with hepatitis C virus (HCV). However, the role of these polymorphisms in protecting injection drug users who are at high risk for HCV infection but do not have detectable antibodies against HCV or HCV RNA (exposed uninfected) has not been demonstrated. We investigated whether these individuals have the IL28B genotype rs12979860-CC, which protects some individuals against HCV infection. METHODS:Seventy-four exposed uninfected individuals, 89 spontaneous resolvers, and 234 chronically infected individuals were genotyped to determine single nucleotide polymorphisms at IL28B.rs12979860. RESULTS:Exposed, uninfected individuals had a significantly lower frequency of the protective genotype (rs12979860-CC) than anti-HCV-positive spontaneous resolvers (41.9% vs 69.7%, respectively; P=.0005; odds ratio [OR], 0.31; 95% confidence interval [CI]: 0.16-0.60) but a similar frequency to patients who were chronically infected (41.9% vs 43.6%, respectively; P=ns). However, exposed, uninfected individuals had a significantly higher frequency of homozygosity for killer cell immunoglobulin-like receptor 2DL3:group 1 HLA-C (KIR2DL3:HLA-C1) than those with chronic infection (31.1% vs 13.3%, respectively; P=.0008; OR, 2.95; 95% CI: 1.59-5.49). For patients who spontaneously resolved infection, IL28B and KIR:HLA protected, independently, against chronic HCV infection, based on logistic regression and synergy analyses (synergy factor, 1.3; 95% CI: 0.37-4.75; P synergy=.6). CONCLUSIONS:IL28B and KIR2DL3:HLA-C1 are independently associated with spontaneous resolution of viremia following HCV exposure. Resistance to HCV infection in exposed uninfected cases is associated with homozygosity for KIR2DL3:HLA-C1 but not the single nucleotide polymorphism IL28B.rs12979860. Uninfected individuals are therefore a distinct population from patients who spontaneously resolve HCV infection. Distinct, nonsynergistic innate immune mechanisms can determine outcomes of HCV exposure.

SUBMITTER: Knapp S

PROVIDER: S-EPMC3194089 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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A polymorphism in IL28B distinguishes exposed, uninfected individuals from spontaneous resolvers of HCV infection.

Knapp Susanne S Warshow Usama U Ho K M Alexander KM Hegazy Doha D Little Ann-Margaret AM Fowell Andrew A Alexander Graeme G Thursz Mark M Cramp Matthew M Khakoo Salim I SI

Gastroenterology 20110414 1

<h4>Background & aims</h4>Polymorphisms in the interleukin-28B (IL28B) gene are associated with outcomes from infection with hepatitis C virus (HCV). However, the role of these polymorphisms in protecting injection drug users who are at high risk for HCV infection but do not have detectable antibodies against HCV or HCV RNA (exposed uninfected) has not been demonstrated. We investigated whether these individuals have the IL28B genotype rs12979860-CC, which protects some individuals against HCV i ...[more]

PMID: 21600205

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Project description:Hepatitis C virus (HCV) remains a significant public health threat as new 1.75 million HCV infections emerged worldwide. The majority of these infections become persistently infected, while around 30 % spontaneously eliminate the virus. Clinical factors for viral clarification are related to HCV interaction with host immune system, but little is known about the consequences after HCV spontaneous resolution. These individuals are difficult to recruit and study as acute infection is usually asymptomatic, and they will not be identified unless it progress to chronic infection. The study of peripheral blood mononuclear cells (PBMCs) of these patients is crucial, as PBMCs are one of the main HCV extrahepatic reservoirs, and its transcriptional profile provide us information of innate and adaptive immune response against HCV infection. Our research shows novel insight on molecular consequences of spontaneous resolution after an acute HCV infection. 96 Individuals with different HCV exposure status were recruited: spontaneous resolved, chronic infected and healthy controls; and the microRNA profile of their PBMCs were analyzed. Our results indicate similar disruption of miRNA expression on HCV chronic patients and those who spontaneously clarified the infection, compared to control patients. The disrupted miRNAs formed a signature of 21 miRNAs that mainly regulate lipid metabolism. This is the first report showing miRNA profile similarities between chronic HCV patients and spontaneous resolved individuals. Thus, our results suggest that HCV infection promotes molecular alterations in PBMCs that will last longer after HCV spontaneous eradication. This evidences open up new prospects in the management of individuals who spontaneously clarified infection, as they should be monitored and followed to dismiss future HCV-related complications, such us liver diseases complications. The identified miRNA signature could be used as biomarker to monitor HCV fingerprint on HCV-exposed patients.

Project description:BackgroundHost single-nucleotide polymorphisms (SNPs) near the interleukin 28B (IL28B) locus are associated with sustained virological response to antiviral therapy and with spontaneous Hepatitis C Virus (HCV) clearance. Prevalence of these SNPs varies depending on ethnicity. The impact of IL28B SNPs in HCV-infected patients is currently unknown in Uruguay. Therefore, the aim of this study was to evaluate and compare the distribution of polymorphisms in the IL28B gene (rs12979860 and rs8099917) among HCV-infected patients and healthy individuals in Uruguay and thus assess their possible association with the establishment of HCV infection.MethodsDNA was recovered from 92 non-infected individuals and 78 HCV-infected patients and SNPs were determined by RFLP and allelic discrimination by real-time PCR.ResultsThe distribution of rs12979860 genotypes for the infected population was 29.5%-CC, 47.4%-CT and 23.1%-TT and for the control group 45.7%, 42.4% and 11.9%, respectively. Prevalence in both infected and uninfected individuals is similar to that reported in other countries with admixed populations. The distribution of rs8099917 genotypes for the infected population was 57.7%-TT, 27.2%-TG and 14.1%-GG and for the control group 60.9%, 33.7% and 5.4%, respectively. The comparison of rs12979860 genotype distribution between the two populations evidenced a higher prevalence of the favourable genotype (CC) in the uninfected control group (p < 0.05). Additionally, results generated using logistic regression analysis show that individuals carrying rs12979860-TT or CT genotypes have a higher likelihood of developing chronic hepatitis upon infection with HCV, when compared to CC carriers, considering rs8099917 genotype as constant.ConclusionPatients with HCV infection have a statistically significant lower prevalence of the favourable rs12979860 genotype when compared to uninfected individuals; therefore we can establish that only IL28B rs12979860-CT and TT genotypes seem to contribute to the occurrence of chronic HCV infection in the cohort of Uruguayan population studied. Considering that a trend towards a higher frequency of "good" response genotypes was observed in responder patients, we believe that IL28B rs12979860 genotyping could be a useful tool for predicting different therapies outcome, including in the DAA era.

Project description:AIM:To test whether the status of positive cytomegalovirus (CMV) DNA detection adds to the predictive value of IL28B and to further categorize C/T allele carriers. METHODS:This study included 166 chronic hepatitis C (CHC) patients who received combined interferon and ribavirin therapy for 48 wk, 84 spontaneous hepatitis C virus (HCV) resolvers who were positive for IgG anti-HCV antibody and negative for HCV RNA, and 100 healthy subjects who were negative for both HCV antibodies and RNA as controls. Genomic DNA from peripheral blood was used for IL28B rs.12979860 single nucleotide polymorphism (SNP) and CMV DNA detection. A 139 bp fragment containing IL28B SNP was amplified in all subjects by polymerase chain reaction using a specifically designed primer. Then the IL28B rs.12979860 SNP was detected by restriction fragment length polymorphism (RFLP) genotyping. The presence of CMV DNA was tested by amplification of the gB1 gene using nested polymerase chain reaction. The role of CMV and IL28B rs.12979860 SNP genotypes in determining the response rate to combined interferon therapy and clinical status of patients were statistically analyzed. RESULTS:Current data showed that 67% of patients carrying the IL28B 12979860 C/C allele had a sustained viral response (SVR) while the genotypes C/T and TT were associated with lower SVR rates, 50% and 48%, respectively. SVR rates for the C/C allele were lower than other HCV genotypes and/or other populations. Genotype CC was associated with the response to interferon (P = 0.025). Genotype C/C was reduced from 48% in controls to 14% in CHC patients suggesting its protective role against progression to chronicity. The majority of spontaneously cleared subjects (86%) were C/C, confirming its protective role. The C/T allele was present in 71% of CHC patients compared with 38% of controls, so the use of IL28B SNP genotyping only in these patients may be of little value as a predictor of response. CMV reactivation occurred in 40% of CHC patients. Co-infection with CMV seriously diminished the response to interferon (IFN) therapy, with SVR rates in C/C genotypes 87.5% in CMV-negative patients and 12.5% in CMV-positive patients (P < 0.0001). SVR rates among C/T carriers were reduced to < 50% in patients with positive CMV DNA while the non-response rate doubled. These data indicate that a supplemental assay for CMV viremia adds to the prognostic value of IL28B genotyping. CONCLUSION:The results suggest that both genetic (i.e., spontaneous) and therapeutic (IFN-based therapy) arms are complementary in the battle against HCV. CMV DNA testing may be of value to better predict the response to IFN, particularly in IL28B C/T carriers.

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A polymorphism in IL28B distinguishes exposed, uninfected individuals from spontaneous resolvers of HCV infection.

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A polymorphism in IL28B distinguishes exposed, uninfected individuals from spontaneous resolvers of HCV infection.

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