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IL28B polymorphisms associated with therapy response in Chilean chronic hepatitis C patients.

ABSTRACT: AIM:To analyze the association of three IL28B single nucleotide polymorphisms with response to therapy in Chilean patients infected with hepatitis C virus (HCV). METHODS:We studied two groups of patients with chronic HCV infection (genotype 1), under standard combined treatment with pegylated interferon plus ribavirin. One group consisted of 50 patients with sustained virological response, whereas the second group consisted of 49 null responders. In order to analyze the IL28B single nucleotide polymorphisms rs12979860, rs12980275 and rs8099917, samples were used for polymerase chain reaction amplification, and the genotyping was performed by restriction fragment length polymorphism. RESULTS:The IL28B rs12979860 CC, rs12980275 AA and rs8099917 TT genotypes were much more frequently found in patients with sustained virological response compared to null responders (38%, 44% and 50% vs 2%, 8.2% and 8.2%, respectively). These differences were highly significant in all three cases (P < 0.0001). CONCLUSION:The three IL28B polymorphisms studied are strongly associated with sustained virological response to therapy in Chilean patients with chronic HCV (genotype 1).

SUBMITTER: Venegas M

PROVIDER: S-EPMC3180021 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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IL28B polymorphisms associated with therapy response in Chilean chronic hepatitis C patients.

Venegas Mauricio M Villanueva Rodrigo A RA González Katherine K Brahm Javier J

World journal of gastroenterology 20110801 31

<h4>Aim</h4>To analyze the association of three IL28B single nucleotide polymorphisms with response to therapy in Chilean patients infected with hepatitis C virus (HCV).<h4>Methods</h4>We studied two groups of patients with chronic HCV infection (genotype 1), under standard combined treatment with pegylated interferon plus ribavirin. One group consisted of 50 patients with sustained virological response, whereas the second group consisted of 49 null responders. In order to analyze the IL28B sing ...[more]

PMID: 21987611

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Project description:BACKGROUND:Hepatitis C is a global health problem and represents a major cause of liver disease and socioeconomic burden. Effective antiviral therapy may prevent these complications, but the current treatment for patients with chronic hepatitis C virus (HCV) infection does not produce sustained virologic response. Therefore, identification of the determinants of response to treatment is a high priority. A number of host and viral factors have been associated with treatment outcomes. OBJECTIVES:To assess the associations of single nucleotide polymorphisms (SNP) of the IL28B and sustained virologic response (SVR) of patients with chronic hepatitis C to PEG-interferon/ribavirin therapy. MATERIALS AND METHODS:We searched PubMed, Medline and Cochrane Library, and found 7 eligible papers involved in this study. Then we performed a meta-analysis comparing the SVR rate at SNP of the IL28B in individuals with PEG-interferon/ribavirin therapy. Meanwhile, the SVR rate between different races and HCV genotypes was studied. RESULTS:The sustained virologic response rate was higher in patients with the rs12979860 CC and rs8099917 TT alleles in the IL28B SNP, comparing with the rs12979860 CT, or TT and rs8099917 TG or GG. Furthermore, a higher SVR was observed in the Caucasians than in Afro-Americans (OR = 3.85, 95% CI: 3.06-4.83); the percentage of rs12979860 TT genotype was lower in Caucasians (OR = 0.25, 95% CI: 0.20-0.31) and the percentage of rs12979860 CC genotype was higher in Caucasians than that of Afro-Americans (OR = 3.45, 95% CI = 2.68-4.44). Between different HCV genotypes, the SVR was much lower in those with HCV genotype 1 than those with genotype 2/3 (OR = 0.16, 95% CI: 0.11-0.24). CONCLUSIONS:IL28B is significantly associated with response to PEG-interferon/ribavirin therapy of patients with chronic HCV infection. Both the rs12979860 and rs8099917 alleles could be used as independent predictors of the treatment response. The rs12979860 allele in particular, is more important from our study. The polymorphism even explains part the difference in response rate between different ethnic groups and HCV genotypes.

Project description:Several SNPs located in or around the IL28B gene are associated with response of patients infected with Hepatitis C virus to treatment with pegylated interferon-α ⁺/⁻ ribavirin or with spontaneous clearance of the virus. The results of such studies are so compelling that future treatment approaches are likely to involve clinical decisions being made on the basis of a patient's genotype. Since IL28B is a paralogue of IL28A with greater than 95% sequence identity, it is possible that without genotyping assay specificity, sequences in IL28A may contribute to genotype identification, and potentially confound treatment decisions. This study aimed to 1) examine DNA sequences in IL28B surrounding each of the reported associated SNPs and the corresponding regions in IL28A; and 2) develop a robust assay for rs12979860, the most 'cosmopolitan' SNP most strongly associated with treatment response across all global populations studied to date. Bioinformatic analysis of genomic regions surrounding IL28A and IL28B demonstrated that 3 SNPs were unique to IL28B, whereas the remaining 6 SNP regions shared >93% identity between IL28A and IL28B. Using a panel of DNA samples, PCR amplification followed by Sanger sequencing was used to examine IL28B SNPs and the corresponding regions in IL28A. For the overlapping SNPs, all 6 in IL28B were confirmed to be polymorphic whereas the corresponding positions in IL28A were monomorphic. Based upon IL28A and IL28B sequence data, a specific TaqMan® assay was developed for SNP rs12979860 that was 100% concordant to the sequence-derived genotypes. Analysis using a commercial assay identified one discordant result which led to a change in their genotype-calling algorithm. Where future treatment decisions are made upon the results of genotyping assays, it is very important that results are concordant with data from a sequence-based format. This is especially so in situations where designing specific PCR primers is a challenge.

Project description:INTRODUCTION:Polymorphisms near the IL28B gene (e.g. rs12979860) encoding interferon ?3 have recently been associated with both spontaneous clearance and treatment response to pegIFN/RBV in chronic hepatitis C (CHC) patients. The molecular consequences of this genetic variation are unknown. To gain further insight into IL28B function we assessed the association of rs12979860 with expression of protein quantitative traits (pQTL analysis) generated using open-platform proteomics in serum from patients. METHODS:41 patients with genotype 1 chronic hepatitis C infection from the Duke Liver Clinic were genotyped for rs12979860. Proteomic profiles were generated by LC-MS/MS analysis following immunodepletion of serum with MARS14 columns and trypsin-digestion. Next, a latent factor model was used to classify peptides into metaproteins based on co-expression and using only those peptides with protein identifications. Metaproteins were then analyzed for association with IL28B genotype using one-way analysis of variance. RESULTS:There were a total of 4,186 peptides in the data set with positive identifications. These were matched with 253 proteins of which 110 had two or more associated, identified peptides. The IL28B treatment response genotype (rs12979860_CC) was significantly associated with lower serum levels of corticosteroid binding globulin (CBG; p?=?9.2×10(-6)), a major transport protein for glucocorticoids and progestins. Moreover, the CBG metaprotein was associated with treatment response (p?=?0.0148), but this association was attenuated when both IL28B genotype and CBG were included in the model, suggesting that the CBG association may be independent of treatment response. CONCLUSIONS:In this cohort of chronic hepatitis C patients, IL28B polymorphism was associated with serum levels of corticosteroid binding globulin, a major transporter of cortisol, however, CBG does not appear to mediate the association of IL28B with treatment response. Further investigation of this pathway is warranted to determine if it plays a role in other comorbidities of HCV-infection.

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IL28B polymorphisms associated with therapy response in Chilean chronic hepatitis C patients.

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IL28B polymorphisms associated with therapy response in Chilean chronic hepatitis C patients.

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