Can we include genetic variants with high linkage disequilibrium into a multiple logistic model?

Impact of IFNL4 rs12979860 and rs8099917 polymorphisms on response to Peg-Interferon-α and Ribavirin in patients with congenital bleeding disorder and chronic hepatitis C

BACKGROUND

The aim of this study was to determine whether two polymorphisms of the human interferon lambda 4 (IFNL4) gene (rs12979860 and rs8099917) can predict sustained virologic response (SVR) following antiviral therapy in patients with inherited bleeding disorder and chronic hepatitis C (CHC).

METHODS

This retrospective study was conducted on 294 patients with congenital bleeding disorder and CHC who were treated with Peg-Interferon-α (PegIFN) and Ribavirin (RBV). Baseline patient and viral parameters were measured and analyzed statistically to assess their combined and individual contributions to SVR prediction.

RESULTS

The most prevalent variants of rs12979860 and rs8099917 identified among the study patients were CT (45.9%) and TT (57.6%), respectively. Overall, SVR was achieved in 69% of the study patients. The rate of SVR was lower in patients with HCV genotype-1 than in those with HCV genotype-3 (62% vs 88%; P<.001; OR=0.23). Multivariate analysis of SVR predictors in patients with HCV genotype-1 infection included age (<24 years), BMI (<25), absence of cirrhosis, HCV RNA level (<400 000 IU/mL), rs8099917 TT and rs12979860 CC, all of which were associated with a higher SVR rate. In HCV genotype-3 infection, only rs12979860 CC was significantly associated with SVR.

CONCLUSION

These results demonstrate that polymorphisms of the IFNL4 gene are highly associated with SVR to PegIFN and RBV combination therapy in patients with a congenital bleeding disorder and CHC. Assessment of rs12979860 and rs8099917 genotypes can guide physicians in choosing an optimal treatment regimen, including less expensive therapies that may only be available in many geographic locales.

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.

The Role of Polymorphisms Near the IL28B Gene on Response to Peg-Interferon and Ribavirin in Thalassemic Patients With Hepatitis C

BACKGROUND

Hepatitis C Virus (HCV) is the major cause of liver failure in thalassemic patients. In these patients, iron overload and their comorbidities make difficulties during Pegylated-Interferon (PEG-IFN) and Ribavirin (RBV) therapy.

OBJECTIVES

We aimed to assess the impact of polymorphisms near the IL28B gene on virological response in HCV - infected thalassemic patients, who were treated with PEG-IFN and RBV.

PATIENTS AND METHODS

This cross - sectional study was conducted on 143 thalassemic patients with chronic hepatitis C, who were treated with a combination of PEG-IFN and RBV regimen. The rs12979860 and rs8099917 polymorphisms were assessed as the most common polymorphisms near the IL28B gene by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The rate of sustained virological response (SVR) was significantly lower in thalassemic patients with HCV genotype-1 infection compared to patients with HCV genotype-3 infection. Among baseline predictors, rs12979860 and rs8099917 polymorphisms were found to be the only parameters associated with achievement of SVR in thalassemic patients with HCV genotype-1 infection however, there was no association between these polymorphisms and the rate of SVR in thalassemic patients with HCV genotype-3 infection.

CONCLUSIONS

In HCV genotype-1- infected thalassemic patients with rs12979860 CC genotype and without severe comorbidities, PEG-IFN and RBV combination therapy can be tried yet in those with rs12979860 CT/TT it may be reasonable to treat cases with new direct-acting antivirals.