Suppressor of cytokine signal 3 and IL28 genetic variation predict the viral response to peginterferon and ribavirin

Interleukin 28B polymorphisms as predictors of sustained virological response in chronic hepatitis C: systematic review and meta-analysis

Polymorphism of interleukin 28B gene represents a powerful outcome predictor for interferon-based regimens in hepatitis C virus infection. However, some studies report conflicting results. The predictive value of interleukin 28B genotype over the outcome interferon-α/ribavirin treatment was thoroughly evaluated and compared with virological predictors of response. Literature revision was performed on PubMed. Pooled odds ratios (ORs) were calculated by fixed- or random-effects models. Heterogeneity and publication bias were also assessed. Sixty-two eligible papers including 20 290 patients were retrieved. Both polymorphisms (rs12979860 and rs8099917) were strongly associated with response (OR=4.09 and 4.00, respectively), however, the association was weaker for subjects infected with viral genotypes 2 and 3 (OR=1.52 and 1.49, respectively). Compared with interleukin 28B genotype, the association with response was lower for baseline viremia (OR=2.15) and higher for rapid virological response (OR=13.86). These results provide a critical evaluation of interleukin 28B genotype as a pharmacogenetic predictor in hepatitis C patients.

Suppressor of cytokine signaling 1 expression in peripheral blood mononuclear cells of hepatitis C genotype 1 patients

BACKGROUND/PURPOSE

While new direct-acting antiviral therapies for hepatitis C virus (HCV) are the standard of care, interferon-α (IFN-α) remains a standard therapy in Taiwan based on its low cost and high response rate to IFN-α-based therapy. IFN-α exerts antiviral activity by inducing the expression of hundreds of genes that establish an antiviral state via Jak kinase (JAK)/signal transducers and activators of transcription (STAT) signaling. We quantified the transcript levels of JAK/STAT signaling genes in peripheral blood mononuclear cells of HCV genotype 1 patients and estimated the correlation between transcript levels and patient responses to IFN-α-based therapy.

METHODS

A total of 100 HCV genotype 1 naïve patients were enrolled. All patients received response-guided therapy for 24-48 weeks with pegylated IFN-α and ribavirin. Peripheral blood mononuclear cells were collected before treatment. Twenty patients with sustained virological responses (SVR) and 20 patients without SVR were selected for a JAK/STAT signaling genes transcript analysis using multiplex reverse transcription-polymerase chain reaction. Transcripts that were upregulated or downregulated were further validated in 100 patients.

RESULTS

Suppressor of cytokine signaling 1 (SOCS1) expression was upregulated in SVR patients compared with non-SVR patients (relative quantification = 2.14) based on a multiplex reverse transcription-polymerase chain reaction analysis. We further analyzed SOCS1 expression in 100 patients. We found that SOCS1 expression did not differ significantly between SVR and non-SVR patients.

CONCLUSION

Peripheral blood SOCS1 expression before treatment was not associated with SVR in HCV genotype 1 patients treated with pegylated IFN-α and ribavirin.

SOCS-1 promoter methylation and treatment response in chronic hepatitis C patients receiving pegylated-interferon/ribavirin

PURPOSE

Suppressor of cytokine signaling-1 (SOCS-1) is a negative regulator of the Janus kinase/signal transducer and activation of transcription pathway. The purpose of this study was to investigate the relationship between methylation of SOCS-1 and sustained virologic response (SVR) in chronic hepatitis C (CHC) patients treated with pegylated interferon (PEG-IFN)-alpha and ribavirin (RBV).

METHODS

In total, 106 CHC patients treated with PEG-IFN-alpha and RBV were included. Serum samples were obtained at baseline (P), end of treatment (EOT), and 6 months post treatment (F6). Methylation status of the promoter region of SOCS-1 was examined by quantitative methylation specific PCR (qMSP).

RESULTS

Median baseline methylation level of SOCS-1 was -0.95 log10 copies/mL, which increased to 0.57 log10 copies/mL at EOT and then returned to -0.57 log10 copies/mL at F6 (baseline vs EOT, P < 0.001; EOT vs F6, P < 0.001). The overall SVR was 75.5%. Univariate analysis indicated that SVR was significantly associated with genotype, baseline HCV RNA, body mass index (BMI) and higher EOT SOCS-1 methylation. Multivariate analysis confirmed that the SVR was significantly associated with genotype (OR: 13.40, 95% CI: 1.73-103.58, P = 0.013), baseline HCV RNA (OR: 0.19, 95% CI: 0.06-0.59, P = 0.004), BMI (OR: 0.73, 95% CI: 0.56-0.96, P = 0.022), and EOT SOCS-1 methylation (OR: 1.71, 95% CI: 1.11-2.62, P = 0.014).

CONCLUSION

CHC patients with significantly higher SOCS-1 methylation at the end of treatment had better SVRs. The role of SOCS-1 methylation in affecting treatment response deserves further investigation.

Meta-analysis: implications of interleukin-28B polymorphisms in spontaneous and treatment-related clearance for patients with hepatitis C

BACKGROUND

Since 2009, several studies have identified single-nucleotide polymorphisms (SNPs) near the gene encoding for interleukin (IL)-28 (IL28B) that are strongly associated with spontaneous and treatment-induced hepatitis C virus (HCV) clearance. Because this large amount of data includes some inconsistencies, we consider assessment of the global estimate for each SNP to be essential.

METHODS

Relevant studies assessing IL28B polymorphisms associated with sustained virologic response (SVR) and spontaneous clearance (SC) were identified from a literature search of PubMed up to 9 July, 2012. Studies were eligible studies if they included patients infected with HCV or HCV/HIV, or assessed any SNP located within or near the IL28B gene, SVR data available under standard treatment, and/or SC data in patients with acute HCV infection. Pooled odds ratios were estimated by fixed or random effects models when appropriate. Variables such as HCV genotype, ethnicity, and type of co-infection were studied.

RESULTS

Of 282 screened studies, 67 were selected for SVR and 10 for SC. In total, 20,163 patients were studied for SVR and 3,554 for SC. For SVR, we found that all SNPs showed strong associations in patients with HCV genotypes 1 and 4, whereas the pooled ORs were almost three times lower for genotypes 2 and 3 (rs12979860 and rs8099917). Regarding ethnicity, the SNP most associated with SVR was rs12979860 in white patients, whereas in East Asians it seemed to be rs8099917. The most studied SNP (rs12979860) showed similar results for patients co-infected with HCV/HIV, as for those infected with HCV only. Finally, rs12979860 and rs8099917 both appeared to be associated with SC.

CONCLUSIONS

IL28B polymorphisms influence both the outcome of interferon treatment and the natural clearance of HCV. However we did not identify a universal predictor SNP, as the best genetic markers differed depending on patient ethnicity, genotype, and type of infection. Nevertheless, our results may be useful for more precise treatment decision-making.

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.

Roles of ITPA and IL28B genotypes in chronic hepatitis C patients treated with peginterferon plus ribavirin

It has been reported that inosine triphosphatase (ITPA) gene variants protect against ribavirin-induced anemia in patients treated for chronic hepatitis C. IL28B variants also influence the treatment response of peginterferon plus ribavirin treatment in these patients. In the present study, we examined how ITPA and IL28B genotypes have clinical impacts on treatment-induced hematotoxicities and treatment response in HCV-infected patients treated with peginterferon plus ribavirin. ITPA genotypes (rs1127354 and rs6051702) and IL28B genotype (rs8099917) were determined by TaqMan SNP assay. We compared clinical background, treatment course and treatment response in terms of these genotypes. Only IL28B rs8099917 major type could predict sustained virological response. ITPA rs1127354 major type leads to significantly greater ribavirin-induced anemia than ITPA rs1127354 minor type between days 0 and 84. We noticed that IL28B rs8099917 minor genotype was associated with higher reduction of neutrophils and platelets. ITPA rs1127354 is useful for the prediction of ribavirin-induced anemia in the early phase after the commencement of peginterferon plus ribavirin treatment and IL28B rs8099917 is useful for the prediction of sustained virological response. Use of the combination of these two genotypes could lead to safe and effective treatment of chronic hepatitis C patients.