Influence of vitamin D-related gene polymorphisms (CYP27B and VDR) on the response to interferon/ribavirin therapy in chronic hepatitis C

Treatment outcome and germline predictive factors of ropeginterferon alpha-2b in myeloproliferative neoplasm patients

BACKGROUND

Studies have shown that some single nucleotide polymorphisms (SNPs) could serve as excellent markers in foretelling the treatment outcome of interferon (IFN) in myeloproliferative neoplasms (MPN). However, most work originated from western countries, and data from different ethnic populations have been lacking.

METHODS

To gain insights, targeted sequencing was performed to detect myeloid-associated mutations and SNPs in eight loci across three genes (IFNL4, IFN-γ, and inosine triphosphate pyrophosphatase [ITPA]) to explore their predictive roles in our cohort of 21 ropeginterferon alpha-2b (ROPEG)-treated MPN patients, among whom real-time quantitative PCR was also performed periodically to monitor the JAK2V617F allele burden in 19 JAK2V617F-mutated cases.

RESULTS

ELN response criteria were adopted to designate patients as good responders if they achieved complete hematological responses (CHR) within 1 year (CHR1) or attained major molecular responses (MMR), which occurred in 70% and 45% of the patients, respectively. IFNL4 and IFN-γ gene SNPs were infrequent in our population and were thus excluded from further analysis. Two ITPA SNPs rs6051702 A>C and rs1127354 C>A were associated with an inferior CHR1 rate and MMR rate, respectively. The former seemed to be linked to grade 2 or worse hepatotoxicity as well, although the comparison was of borderline significance only (50%, vs. 6.7% in those with common haplotype, p = 0.053). Twelve patients harbored 19 additional somatic mutations in 12 genes, but the trajectory of these mutations varied considerably and was not predictive of any response.

CONCLUSIONS

Overall, this study provided valuable information on the ethnics- and genetics-based algorithm in the treatment of MPN.

The Identification of Admixture Patterns Could Refine Pharmacogenetic Counseling: Analysis of a Population-Based Sample in Mexico

Pharmacogenetic analysis has generated translational data that could be applied to guide treatments according to individual genetic variations. However, pharmacogenetic counseling in some mestizo (admixed) populations may require tailoring to different patterns of admixture. The identification and clustering of individuals with related admixture patterns in such populations could help to refine the practice of pharmacogenetic counseling. This study identifies related groups in a highly admixed population-based sample from Mexico, and analyzes the differential distribution of actionable pharmacogenetic variants. A subsample of 1728 individuals from the Mexican Genomic Database for Addiction Research (MxGDAR/Encodat) was analyzed. Genotyping was performed with the commercial PsychArray BeadChip, genome-wide ancestry was estimated using EIGENSOFT, and model-based clustering was applied to defined admixture groups. Actionable pharmacogenetic variants were identified with a query to the Pharmacogenomics Knowledge Base (PharmGKB) database, and functional prediction using the Variant Effect Predictor (VEP). Allele frequencies were compared with chi-square tests and differentiation was estimated by F_ST. Seven admixture groups were identified in Mexico. Some, like Group 1, Group 4, and Group 5, were found exclusively in certain geographic areas. More than 90% of the individuals, in some groups (Group 1, Group 4 and Group 5) were found in the Central-East and Southeast region of the country. MTRR p.I49M, ABCG2 p.Q141K, CHRNA5 p.D398N, SLCO2B1 rs2851069 show a low degree of differentiation between admixture groups. ANKK1 p.G318R and p.H90R, had the lowest allele frequency of Group 1. The reduction in these alleles reduces the risk of toxicity from anticancer and antihypercholesterolemic drugs. Our analysis identified different admixture patterns and described how they could be used to refine the practice of pharmacogenetic counseling for this admixed population.

Effects of vitamin D on drugs: Response and disposal

Vitamin D supplementation and vitamin D deficiency are common in clinical experience and in daily life. Vitamin D not only promotes calcium absorption and immune regulation, but also changes drug effects (pharmacodynamics and adverse reactions) and drug disposal in vivo when combined with various commonly used clinical drugs. The extensive physiological effects of vitamin D may cause synergism effects or alleviation of adverse reactions, and vitamin D's affect on drugs in vivo disposal through drug transporters or metabolic enzymes may also lead to changes in drug effects. Herein, the effects of vitamin D combined with commonly used drugs were reviewed from the perspective of drug efficacy and adverse reactions. The effects of vitamin D on drug transport and metabolism were summarized and analyzed. Hopefully, more attention will be paid to vitamin D supplementation and deficiency in clinical treatment and drug research and development.

Genetic associations of vitamin D receptor polymorphisms with advanced liver fibrosis and response to pegylated interferon-based therapy in chronic hepatitis C

Vitamin D receptor (VDR) modulates host immune responses to infections such as hepatitis C virus (HCV) infection, including interferon signaling. This study aimed to investigate the associations of VDR polymorphisms with advanced liver fibrosis and response to pegylated interferon (PEG-IFN)-based therapy in patients with chronic HCV infection. In total, 554 Thai patients with chronic HCV infection treated with a PEG-IFN-based regimen were enrolled. Six single-nucleotide polymorphisms (SNPs) were genotyped: the IL28B C > T (rs12979860) SNP and five VDR SNPs, comprising FokI T > C (rs2228570), BsmI C > T (rs1544410), Tru9I G > A (rs757343), ApaI C > A (rs7975232), and TaqI A > G (rs731236). In total, 334 patients (60.3%) achieved sustained virological response (SVR), and 255 patients (46%) were infected with HCV genotype 1. The bAt (CCA) haplotype, consisting of the BsmI rs1544410 C, ApaI rs7975232 C, and TaqI rs731236 A alleles, was associated with poor response (in terms of lack of an SVR) to PEG-IFN-based therapy. The IL28B rs12979860 CT/TT genotypes (OR = 3.44, 95% CI [2.12–5.58], p < 0.001), bAt haplotype (OR = 2.02, 95% CI [1.04–3.91], p = 0.03), pre-treatment serum HCV RNA (logIU/mL; OR = 1.73, 95% CI [1.31–2.28], p < 0.001), advanced liver fibrosis (OR = 1.68, 95% CI [1.10–2.58], p = 0.02), and HCV genotype 1 (OR = 1.59, 95% CI [1.07–2.37], p = 0.02) independently predicted poor response. Patients with the bAt haplotype were more likely to have poor response compared to patients with other haplotypes (41.4% vs 21.9%, p = 0.03). The FokI rs2228570 TT/TC genotypes (OR = 1.63, 95% CI [1.06–2.51], p = 0.03) and age ≥55 years (OR = 2.25; 95% CI [1.54–3.32], p < 0.001) were independently associated with advanced liver fibrosis, assessed based on FIB-4 score >3.25. VDR polymorphisms were not associated with pre-treatment serum HCV RNA. In Thai patients with chronic HCV infection, the bAt haplotype is associated with poor response to PEG-IFN-based therapy, and the FokI rs2228570 TT/TC genotypes are risk factors for advanced liver fibrosis.

Association of vitamin-D-related genetic variations and treatment response to pegylated interferon in patients with chronic hepatitis B

BACKGROUND

Vitamin D, a potent immune-modulator, has been linked to the pathogenesis of chronic hepatitis B (CHB). This study was aimed at investigating the association between single nucleotide polymorphisms (SNPs) in vitamin-D-related genes and treatment response to pegylated interferon (PEG-IFN) in patients with CHB.

METHODS

A total of 275 Thai patients (122 hepatitis B e antigen [HBeAg]-positive and 153 HBeAg-negative CHB) treated with 48-week PEG-IFN were recruited. Virological response (VR) at 48 weeks post-treatment was defined as HBeAg seroconversion plus HBV DNA <2,000 IU/ml for HBeAg-positive CHB and HBV DNA <2,000 IU/ml for HBeAg-negative CHB. The SNPs VDR (rs2228570), DBP (rs7041) and CYP27B1 (rs4646536) were analysed.

RESULTS

The distribution of TT, CT and CC genotypes of rs4646536 in this cohort was 21.8%, 46.2% and 32.0%, respectively. There was no difference in its distribution according to HBeAg status. In HBeAg-positive CHB, patients with TT genotype, compared with non-TT genotype, achieved higher VR (53.3% versus 31.5%; P=0.032) and hepatitis B surface antigen (HBsAg) clearance (20.0% versus 5.4%; P=0.016). In HBeAg-negative CHB, the corresponding figures were 60.0% versus 30.9% (P=0.003) and 16.7% versus 5.7% (P=0.045), respectively. Patients with TT genotype had more rapid HBsAg decline than those with non-TT genotype. However, SNPs rs2228570 and rs7041were not associated with VR and HBsAg clearance. Logistic regression analysis demonstrated that SNP rs4646536 and baseline HBsAg level were independent predictors of VR in both HBeAg-positive and HBeAg-negative CHB.

CONCLUSIONS

Our data suggest that SNP rs4646536 in the CYP27B1 gene is a predictive factor of response to PEG-IFN therapy in Thai patients with CHB.

Role of VDR, GC, and CYP2R1 Polymorphisms in the Development of Hepatocellular Carcinoma in Hepatitis C Virus-Infected Patients

Aims: This study was designed to determine if vitamin D receptor (VDR), carrier globulin/binding protein (GC), and cytochrome P-450 family 2, subfamily R, polypeptide 1 (CYP2R1) gene polymorphisms are risk factors in the development of hepatocellular carcinoma (HCC) in hepatitis C virus (HCV)-infected patients from Northeast India. Materials and Methods: A total of 351 HCV-infected patients were enrolled of which 167 were diagnosed with chronic hepatitis C (CHC), 124 with liver cirrhosis (LC), and 60 with HCC together with 102 age- and sex-matched healthy controls. VDR (BsmI, ApaI, and TaqI), GC (rs4588, rs7051), and CYP2R1 (rs10741657) gene polymorphisms were genotyped for all subjects. Statistical data were analyzed using SPSS ver. 22.0. Results: The frequency of the ApaI CC genotype, ApaI C allele, and bAt haplotype of the VDR gene was significantly higher in HCC and LC patients than controls. After adjusting for other covariates (age, gender, platelet count, AST, ALT, serum albumin, and viral load) logistic regression analysis showed that the ApaI CC genotype and bAt haplotype were independent predictors of HCC development. No significant associations was found for the GC and CYP2R1 polymorphisms examined with the occurrence of HCC. Conclusions: The presence of the VDR ApaI CC genotype and bAt haplotype appear to be important indicators in the development of HCC among HCV-infected patients. Larger studies are needed to further clarify and establish this potential causal relationship.

Vitamin D deficiency in hepatitis C virus infection: what is old? what is new?

In the past few years, a growing body of clinical evidence has highlighted the risk of vitamin D deficiency in patients with chronic hepatitis C and that vitamin D levels are associated with the course of hepatitis C virus (HCV) infection, adverse effects, and treatment response to peginterferon/ribavirin. Recently, studies have found that vitamin D status is related to drug resistance and increased risk of infection in patients with liver cirrhosis. Vitamin D-related gene polymorphisms have been found to explain the interactions between vitamin D deficiency and HCV infection, offering a new perspective toward understanding the current problems such as the development of insulin resistance and racial differences in sustained virological response. Studies have been conducted to determine whether vitamin D supplementation as an adjuvant yields a better result compared with traditional HCV treatment. Here, we provide a brief review of the past and present knowledge of vitamin D in HCV infection.

Vitamin D and the Liver-Correlation or Cause?

Vitamin D is becoming increasingly accepted as an important physiological regulator outside of its classical role in skeletal homeostasis. A growing body of evidence connects vitamin D with hepatic disease. This review summarises the role of vitamin D in liver homeostasis and disease and discusses the therapeutic potential of vitamin D-based treatments to protect against hepatic disease progression and to improve response to treatment. While pre-clinical experimental data is promising, clinical trials around liver diseases have mostly been under-powered, and further studies will be required to clarify whether vitamin D or vitamin D analogues have beneficial effects on liver disease.

Influence of Vitamin D Receptor Gene Polymorphisms on Response to Pegylated Interferon in Chronic Hepatitis B Egyptian Patients

BACKGROUND

We explored the effect of vitamin D receptor gene (VDR) polymorphisms in response to PEG-IFN treatment in Egyptian chronic hepatitis B (CHB) patients.

METHODS

Two hundred hepatitis B virus (HBV) patients (42.3±10.7 years) on PEG-IFN α-2a (180 µg /kg for 48 weeks) and one hundred control subjects (37.3 ±12 years) were enrolled in the study. Vitamin D levels and hepatitis B surface antigen (HBsAg) expression were assessed by ELISA. VDR polymorphisms FokI T>C (rs 10735810), BsmI A>G (rs 1544410), ApaI (rs7975253), and TaqI C>T (rs 731236), were genotyped using real-time PCR.

RESULTS

Hepatitis B virus patients expressed significantly greater AST (p=< 0.00001) and ALT (P=< 0.00001), and significantly less vitamin D (P=0.01), than control subjects. Patients with Ff or ff alleles of the FokI single-nucleotide polymorphism (SNP), bb alleles of BsmI SNP, or TT alleles of the Taq1 single nucleotide polymorphisms (SNP) showed greater response to PEG-IFN therapy than those with the FF (P=0.02 and P=0.0002), Bb (P=0.023), or Tt/tt alleles (P=0.01 and P=0.004 respectively). Logistic stepwise regression showed that HBV DNA (r: 0.910, P< .00001), FokI SNP polymorphism (r: 0.919, (P=0.037) and bAt haplotype (r: .926, (P=0.043) are independent factors that determine PEG-IFN treatment response in the HBV-infected patients.

CONCLUSION

VDR gene polymorphisms may be used as treatment response predictors in HBV patients receiving PEG-IFN. FokI SNP and bAt haplotype are independent factors that that can be used to determine PEG-IFN treatment responses in HBV-infected patients.

Nuclear receptor gene polymorphisms and warfarin dose requirements in the Quebec Warfarin Cohort

Warfarin is primarily metabolized by cytochrome 2C9, encoded by gene CYP2C9. Here, we investigated whether variants in nuclear receptor genes which regulate the expression of CYP2C9 are associated with warfarin response. We used data from 906 warfarin users from the Quebec Warfarin Cohort (QWC) and tested the association of warfarin dose requirement at 3 months following the initiation of therapy in nine nuclear receptor genes: NR1I3, NR1I2, NR3C1, ESR1, GATA4, RXRA, VDR, CEBPA, and HNF4A. Three correlated SNPs in the VDR gene (rs4760658, rs11168292, and rs11168293) were associated with dose requirements of warfarin (P = 2.68 × 10^-5, P = 5.81 × 10^-4, and P = 5.94 × 10^-4, respectively). Required doses of warfarin were the highest for homozygotes of the minor allele at the VDR variants (P < 0.0026). Variants in the VDR gene were associated with the variability in response to warfarin, emphasizing the possible clinical relevance of nuclear receptor gene variants on the inter-individual variability in drug metabolism.

Vitamin D-related gene polymorphism predict treatment response to pegylated interferon-based therapy in Thai chronic hepatitis C patients

Background

Patients with chronic hepatitis C (HCV) infection have high prevalence of vitamin D deficiency. Genome-wide association study data has showed that several genetic variants within vitamin D cascade affect vitamin D function. This study aimed to determine whether genetic polymorphisms of genes in the vitamin D pathway are associated with treatment responses to pegylated interferon (PEG-IFN)-based therapy in patients with chronic HCV infection.

Methods

The study included 623 Thai patients from 2 university hospitals diagnosed with chronic HCV infection who were treated with a PEG-IFN and ribavirin. Patients were genotyped for functional variants on vitamin D synthetic pathway including GC (rs4588, rs7041, rs22020, rs2282679), CYP2R1 (rs2060793, rs12794714), CYP27B1 (rs10877012), and DHCR7 (rs12785878). Pre-treatment predictors of sustained virologic response (SVR) at 24 weeks following discontinuation of therapy were identified using a logistic regression analysis.

Results

SVR was achieved by 60.5% of patients (52.9% with HCV genotype 1; 66.7% with HCV non-genotype 1). In 44.6% of HCV genotype 1-infected patients, only the variant rs12785878 in the DHCR7 locus was significantly associated with an SVR. HCV genotype 1 patients who had DHCR7 rs12785878 GT/TT had a higher rate of SVR than those with the GG allele (59.7% vs. 43.4%, P = 0.03), but in HCV non-genotype 1-infected patients, the SVR rate did not differ between the two groups (63.3% and 59.1% for GT/TT and GG allele, P = 0.54). By multivariate analysis, liver fibrosis stage 0–1 (OR = 5.00; 95% CI, 2.02–12.37; P < 0.001), and DHCR7 rs12785878 GT/TT allele (OR = 2.69; 95% CI, 1.03–7.05; P = 0.04) were independent pre-treatment predictors of SVR following PEG-IFN-based therapy in HCV genotype 1 patients. Baseline HCV RNA < 400,000 IU/ml (OR = 1.96; 95% CI, 1.13–3.39; P = 0.02) was the only independent predictor of SVR in HCV non-genotype 1 patients. The polymorphisms of GC, CYP2R1 and CYP27B1 were not associated with treatment outcome even in genotype 1 or non-genotype 1 HCV infection.

Conclusion

The DHCR7 polymorphism may be a pre-treatment predictive marker for response to PEG-IFN-based therapy in chronic HCV genotype 1 infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-017-0613-x) contains supplementary material, which is available to authorized users.

Genetic variation in the vitamin D pathway CYP2R1 gene predicts sustained HBeAg seroconversion in chronic hepatitis B patients treated with pegylated interferon: A multicenter study

Evidence of a role of vitamin D in the immune system is increasing. Low serum vitamin D is associated with increased hepatitis B virus replication. Genome-wide association study (GWAS) data has revealed a number of the single nucleotide polymorphisms (SNPs) within the vitamin D synthetic pathway that affect vitamin D functions. We aimed to determine the association between SNPs in the vitamin D gene cascade and response to pegylated interferon (PegIFN) therapy in hepatitis B e-antigen (HBeAg)-positive patients. One hundred and eleven patients treated for 48 weeks with PegIFN-alfa 2a at 13 hospitals were retrospectively evaluated. Thirteen SNPs derived from vitamin D cascade-related genes, including DHCR7 (rs12785878), CYP27B1 (rs10877012), CYP2R1 (rs2060793, rs12794714), GC (rs4588, rs7041, rs222020, rs2282679), and VDR (FokI, BsmI, Tru9I, ApaI, TaqI), were genotyped. Thirty-one patients (27.9%) seroconverted to HBeAg after 24 weeks of treatment. Multivariate analysis found pretreatment qHBsAg <10,000 IU/mL (OR = 7.73, 95% CI: 2.36-25.31, P = 0.001), CYP2R1 rs12794714 TT genotype (OR = 4.16, 95% CI: 1.07-16.25, P = 0.04), and baseline ALT >2 times the upper limit of normal (OR = 3.83, 95% CI: 1.31-11.22, P = 0.014) predicted sustained HBeAg seroconversion after completion of PegIFN treatment. HBV DNA during study period tended to be lower with the rs12794714 CYP2R1 TT than the non-TT genotype. The rs12794714 CYP2R1 polymorphism may be a useful pretreatment factor predictive of sustained HBeAg seroconversion after PegIFN therapy. This study provides evidence that not only vitamin D level but also genetic variation of CYP2R1 in the vitamin D cascade influences host immune response in chronic HBV infection.

Vitamin D in liver disease: Current evidence and potential directions

Consistent with its multifaceted nature, growing evidence links vitamin D with hepatic disease. In this review, we summarise the roles of vitamin D in different liver pathologies and explore the clinical utility of vitamin D-based treatments in hepatology. We find that the small number of clinical trials coupled with the profound heterogeneity of study protocols limits the strength of evidence needed to ascribe definite clinical value to the hormone in liver disease. Nevertheless, the experimental data is promising and further bench and bedside studies will likely define a clearer role in hepatic therapeutics.

Molecular assessment of vitamin D receptor polymorphism as a valid predictor to the response of interferon/ribavirin-based therapy in Egyptian patients with chronic hepatitis C

OBJECTIVE

The aim of this study was to find an association between serum concentration of vitamin D and vitamin D receptor (VDR) polymorphisms to achieve a sustained virological response (SVR).

METHODS

We conducted a case-control study in which 250 participants were recruited and divided into three groups (100 chronic hepatitis C [CHC] patients who achieved SVR, 100 CHC patients who did not achieve SVR and 50 apparently healthy individuals as controls). Blood samples were collected to measure serum vitamin D concentration, and four VDR polymorphisms (FokI, ApaI, TaqI, and BsmI) were detected using polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Non-responders were found to have significantly low vitamin D concentration compared with responders and control groups. Concerning VDR polymorphisms, both FokI and TaqI polymorphisms were associated with successful treatment.

CONCLUSION

Vitamin D concentration, FokI, and TaqI may be considered as the predictors for the response of CHC patients to a combination therapy of pegylated interferon and ribavirin.

GAMMA GLUTAMYLTRANSFERASE IMPACT IN THERAPEUTIC RESPONSE OF CHRONIC HEPATITIS C: a systematic review of the literature

BACKGROUND

The standard treatment of chronic hepatitis C is the administration of pegylated interferon α2a or α2b in combination with ribavirin, but adverse effects can be observed, as well as the high cost of this therapy. Therefore, there is interest in understanding the predictors of sustained virologic response, as the gamma glutamyltransferase.

OBJECTIVE

To evaluate the serum levels of gamma glutamyltransferase as a predictor of response to treatment with pegylated interferon α and ribavirin in chronic hepatitis C.

METHODS

This is a systematic review of literature, conducted by consulting PUBMED, LILACS, MEDLINE, SCOPUS, Cochrane electronic databases, and active search of articles selected between January 2000 and April 2013.

RESULTS

A total of 4,785 titles were identified. Out of those material, following inclusion and exclusion criteria, 273 abstracts were selected, by two independent researchers. After reading those texts, the reviewers consensually included ten studies for systematization and classification, according to the criteria of the Oxford Scale. 1B studies are predominant (prospective cohort study - six studies). Rapid virologic response and early virological response were considered as estimates for the sustained virological response. The frequency of virologic response was identified in three studies and early virological response in two, with a total of 392 and 413 patients, respectively; sustained virologic response was reported in nine articles corresponding to 3,787 patients (76.5 %).

CONCLUSION

Gamma glutamyltransferase is a predictor of sustained virologic response in the treatment of chronic hepatitis C with pegylated interferon α2a or α2b associated with ribavirin.

Vitamin D level and vitamin D receptor genetic variations contribute to HCV infection susceptibility and chronicity in a Chinese population

Vitamin D and vitamin D receptor (VDR) are involved in multiple immune-mediated disorders including chronic hepatitis C virus (HCV) infection. The aim of this study was to determine the association between plasma vitamin D level, VDR genetic polymorphisms and risk of HCV infection susceptibility and chronicity. Seven single nucleotide polymorphisms (SNPs) in VDR gene were genotyped and plasma 25-hydroxyvitamin D [25(OH)D] levels were measured in a Han Chinese population of 898 HCV persistent infection cases, 558 spontaneous clearance subjects and 1136 uninfected controls with high risk of HCV infection. In this case-control study, the average plasma 25(OH)D level in persistent infection patients was significantly lower than that in spontaneous clearance cases (P=0.039) and controls (P=0.005). Logistic analyses indicated that rs7975232-C, rs2239185-T and rs11574129-T alleles were significantly associated with a decreased risk of HCV infection susceptibility (all PBonferroni<0.05, in additive/dominant models; Ptrend=9.000×10(-4), combined effects in a locus-dosage manner). The protective effects of three favorable alleles were more evident among males, females and subjects aged ≤50years (all P<0.05). Haplotype analyses suggested that compared with the most frequent haplotype Ars7975232Trs731236Crs11574129, CTT was correlated with a reduced risk of HCV infection susceptibility (P=2.200×10(-3)). These findings implied that low vitamin D levels might be associated with an increased risk for HCV infection and chronicity, and favorable VDR variants (rs7975232-C, rs2239185-T and rs11574129-T) might contribute to a decreased susceptibility to HCV infection in a high-risk Chinese population.

GC Gene Polymorphism and Unbound Serum Retinol-Binding Protein 4 Are Related to the Risk of Insulin Resistance in Patients With Chronic Hepatitis C: A Prospective Cross-Sectional Study

Insulin resistance (IR) is found in chronic hepatitis C (CHC) more frequently than in other chronic liver diseases.Prospective cross-sectional study to evaluate a wide multitest panel to identify factors related with IR in CHC and their possible interactions.In 76 patients with CHC we performed a series of routine laboratory analysis as well as specifically designed serum biochemical tests [retinol, retinol-binding protein 4 (RBP4), 25-OH vitamin D, Vitamin E, lipopolysaccharide-binding protein (LBP), interleukin-6 (IL-6), and cystatin C]. The single nucleotide polymorphisms rs7041 and rs4588 GC-DBP (group-specific component-Vitamin D-binding protein), rs738409 PNPLA3 (patatin-like phospholipase domain containing 3), and rs12979860 IL28B (interleukin-28 B) genes were determined. Insulin sensitivity was established with the HOMA-IR and IR was diagnosed when HOMA-IR > 3. Fibrosis staging was assessed with liver biopsy or transient elastography.After backward logistic regression analysis, independent variables associated with IR were Gc1s/Gc1s DBP phenotype, that results from the homozygous carriage of the rs7041G/rs4588C haplotype (P = 0.033); low retinol/RBP4 ratio, reflecting a greater rate of unbound RBP4 (P = 0.005); older age (P = 0.01); high serum tryglicerides (P = 0.026); and advanced (F3-F4) fibrosis stage. The AUROC provided by the multivariate model was 0.950 (95% CI = 0.906-0.993).In addition to previously known ones, the Gc1s/Gc1s phenotype variant of DBP and the unbound fraction of plasma RBP4 may be considered as factors related with the incidence, and possibly the risk, of IR in CHC patients.

Integrative role of vitamin D related and Interleukin-28B genes polymorphism in predicting treatment outcomes of Chronic Hepatitis C

BACKGROUND

Improving prediction of treatment outcomes in chronic hepatitis C (CHC) genotype 4 (G4) is necessary to increase sustained viral response (SVR) rates. Vitamin D related and interferon stimulated genes are good candidates as they are recently crosstalk altering interferon response. Thus single nucleotide polymorphisms (SNPs) within some of these genes and multiple stepwise regression analysis including other independent predictors (IL28B(rs12979860), serum 25OH-vitamin D, serum alfa-fetoprotein (AFP)) were performed on a cohort of 200 Egyptian CHC patients treated with Pegylated interferon-alpha (Peg-IFN) plus ribavirin.

METHODS

SNPs in cytochrome P-450 (CYP2R1)(rs10741657AG), vitamin D receptor (VDR)(rs2228570AG, rs1544410CT), oligoadenylate synthetases-like (OASL)(rs1169279CT) and adenosine deaminases acting on RNA (ADAR)(rs1127309TC) genes were analyzed by real-time PCR.

RESULTS

The carrier state of A allele in VDR rs2228570 and CYP2R1 rs10741657 genes were independently associated with SVR [OR 6.453 & 3.536, p < 0.01 respectively]. Combining carriers of A allele in CYP2R1 and VDR genes with IL28B C/C genotype increased the probability of SVR from 80 % to reach 87.8 %, 93 % and 100 %. No relation was found between VDR rs1544410CT, ADAR rs1127309TC, OASL rs1169279CT polymorphisms and treatment outcome. Combining VDR rs2228570 A/A genotype with IL28B C/C genotype increased the probability of SVR from 82 % to reach 100 % and from 29 % to reach 80 % in C/T+ T/T IL28B genotype in none F4 liver disease patients.

CONCLUSION

Vitamin D related (VDR rs2228570 and CYP2R1 rs10741657) and IL28B rs12979860 genes polymorphisms accurately assure SVR in naïve CHC G4 patients treated with low cost standard therapy.

Association of vitamin D receptor gene polymorphisms with response to peginterferon plus ribavirin in Asian patients with chronic hepatitis C

BACKGROUND/PURPOSE

Recent studies have shown that serum vitamin D deficiency is a negative predictor of response to peginterferon plus ribavirin therapy for Caucasian patients with chronic hepatitis C (CHC). Whether vitamin D receptor (VDR) gene polymorphisms associate with antiviral response in Asian CHC patients remains unclear.

METHODS

We recruited 139 Asian patients with CHC genotype-1 who achieved 80/80/80 adherence of response-guided peginterferon plus ribavirin therapy. BsmI rs1544410, ApaI rs7975232, and TaqI rs731236 were genotyped and related to clinical and virological features and to treatment outcome.

RESULTS

Patients carrying bAt [CCA] haplotype (p=0.033), ApaI CC genotype (p = 0.033), and TaqI AA genotype (p = 0.037) had a higher HCV load as compared to those with other haplotypes, ApaI CA/AA genotype and TaqI AG genotype, respectively. A sustained virological response (SVR) was achieved in 74 (53%) of the patients. Polymorphisms in VDR gene did not correlate with rapid virological response and SVR achievement. Stepwise logistic regression analysis showed that rs12979860 CC type [odds ratio (OR): 5.56, p=0.007], platelet counts ≥ 15 × 10(10)/L (OR: 4.80, p=0.001), and rapid virological response achievement (OR: 8.36, p<0.001) were independent factors of SVR.

CONCLUSION

Despite their associations with high hepatitis C virus load, VDR gene polymorphisms are not related to the response to peginterferon plus ribavirin therapy in Asian CHC patients.

Vitamin D-related gene polymorphisms do not influence the outcome and serum vitamin D level in pegylated interferon/ribavirin therapy combined with protease inhibitor for patients with genotype 1b chronic hepatitis C

Although several vitamin D-related gene polymorphisms were reported to affect the outcome of pegylated interferon/ribavirin (PR) therapy in chronic hepatitis C patients, there are no reports on the impact of the vitamin D-related gene polymorphisms in PR therapy combined with protease inhibitor (PI). Vitamin D-related gene polymorphisms were determined in 177 genotype 1b-infected chronic hepatitis C patients who received 12 weeks of PR therapy with telaprevir, a first-generation PI, followed by 12 weeks of PR therapy. The sustained virologic response (SVR) rate was 83.1% (147 of 177 patients). The frequencies of vitamin D-related gene polymorphisms were: 83 non-TT and 94 TT genotypes for GC, 97 non-AA and 80 AA genotypes for DHCR7, 151 non-AA and 26 AA genotypes for CYP2R1, 162 non-GG and 15 GG genotypes for CYP27B1, and 105 non-GG and 72 GG genotypes for VDR gene. Multivariate analysis extracted IL28B TT genotype (P = 2.05 × 10(-6)) and serum 25(OH) D3 level (P = 0.024) as independent factors contributing to the achieving of SVR. The SVR rate in IL28B TT genotype patients with serum 25(OH) D3 level of < 25 ng/ml was significantly low compared to other patients. None of the vitamin D-related gene polymorphisms affected the treatment outcome and serum 25(OH) D3 level. In conclusions, the IL28B polymorphism and serum 25(OH) D3 level contributed significantly and independently to SVR in PR combined with PI for genotype 1b-infected chronic hepatitis C patients. However, none of vitamin D-related gene polymorphisms had an impact on the treatment outcome and serum 25(OH) D3 level.

Genetic variations in vitamin D receptor were associated with the outcomes of hepatitis C virus infection among Chinese population

Vitamin D has been considered as an immune modulator, and exerted the effect through the vitamin D receptor (VDR). This study investigated the associations of single-nucleotide polymorphisms (SNPs) of VDR with the outcomes of Hepatitis C virus (HCV) infection. Three SNPs (rs2228570, rs757343 and rs739837) were genotyped by TaqMan assay among Chinese population, including 538 HCV spontaneous clearance subjects, 834 persistent infection subjects and 1030 uninfected subjects. Binary logistic analyses were used to control the effects of confounding factors. The results showed that subjects with the rs757343 A allele and rs739837 A allele had the significantly reduced risk of HCV susceptibility (all PBonferroni<0.05 in dominant/additive model). In the stratified analysis, the protection of rs757343 A allele and rs739837 A allele against HCV infection remained effective in some subgroups. In addition, patients carrying rs739837 CA genotype were less prone to develop persistent infection (PBonferroni=0.033) and such effect still work in several subgroups in the stratified analysis. Furthermore, haplotype analysis indicated that when compared with the most frequent GC haplotype, the haplotype carrying AA (odds ratio (OR)=0.66, 95% confidence interval (CI)=0.56-0.78) and GA (OR=0.64, 95% CI=0.47-0.85) suggested a protective effect. Our findings indicated that the polymorphisms of VDR are associated with the outcomes of HCV infection among Chinese population.

Role of genetic polymorphisms in hepatitis C virus chronic infection

AIM: To analyze the host genetics factors influencing the clinical course and the response to antiviral treatment in patients with chronic hepatitis C (CHC).

METHODS: We conducted an electronic search on the PubMed and MEDLINE (2000-2014) databases and Cochrane library (2000-2014). A total of 73 articles were retrieved and their data were extensively evaluated and discussed by the authors and then analyzed in this review article.

RESULTS: Several studies associated polymorphisms in the interleukin 28B gene on chromosome 19 (19q13.13) with a spontaneous viral clearance in acute hepatitis C and with the response to pegylated interferon (Peg-IFN)-based treatment in chronic hepatitis C patients. Other investigations demonstrated that inosine triphosphate pyrophosphatase genetic variants protect hepatitis C virus-genotype-1 CHC patients from ribavirin-induced anemia, and other studies that a polymorphism in the patatin-like phospholipase domain-containing protein 3 was associated with hepatic steatosis in CHC patients. Although not conclusive, some investigations suggested that the vitamin D-associated polymorphisms play an important role in the achievement of sustained virologic response in CHC patients treated with Peg-IFN-based antiviral therapy. Several other polymorphisms have been investigated to ascertain their possible impact on the natural history and on the response to treatment in patients with CHC, but the data are preliminary and warrant confirmation.

CONCLUSION: Several genetic polymorphisms seem to influence the clinical course and the response to antiviral treatment in patients with CHC, suggesting individualized follow up and treatment strategies.

Association of vdr, cyp27b1, cyp24a1 and mthfr gene polymorphisms with oral lichen planus risk

OBJECTIVES

The current study investigated the association between VDR EcoRV (rs4516035), FokI (rs2228570), ApaI (rs7975232) and TaqI (rs731236), CYP27B1 (rs4646536), CYP24A1 (rs2296241), and MTHFR (rs1801133) gene polymorphisms and risk of oral lichen planus (OLP) occurrence.

MATERIALS AND METHODS

The study group consisted of 65 oral lichen planus patients and 100 healthy blood donors in the control group. Single nucleotide polymorphisms were genotyped by real time PCR or PCR-restriction fragment length polymorphism (RFLP) method.

RESULTS

Heterozygous as well as mutated genotype of vitamin D receptor (VDR) FokI (rs2228570) polymorphism was associated with increased oral lichen planus risk in comparison with wild type genotype (odds ratio (OR) = 3.877, p = 0.017, OR = 38.153, p = 0.001, respectively). A significantly decreased OLP risk was observed for heterozygous genotype of rs2296241 polymorphism in CYP24A1 gene compared with the wild type form (OR = 0.314, p = 0.012). VDR gene polymorphisms ApaI and TaqI were in linkage disequilibrium (D' = 0.71, r(2) = 0.22). Identified haplotype AT was associated with decreased OLP risk (OR = 0.592, p = 0.047).

CONCLUSION

Our results highlight the possible important role of VDR FokI (rs2228570) and CYP24A1 rs2296241 gene polymorphisms for oral lichen planus susceptibility.

CLINICAL RELEVANCE

Identification of new molecular biomarkers could potentially contribute to determination of individuals with OLP predisposition.

Vitamin D and chronic hepatitis C: effects on success rate and prevention of side effects associated with pegylated interferon-α and ribavirin

Chronic hepatitis C (CHC) is one of the most common causes of liver diseases worldwide, affecting 3% of the world population and 3 to 4 million people acquire new infection annually. Despite the recent introduction of novel antiviral drugs for the treatment of CHC, these drugs are expensive and the access to them is not an option for many patients. Hence, the traditional therapy by pegylated interferon-α (Peg-IFN-α) and ribavirin may still have a role in the clinical management of CHC especially in developing countries. However, this standard therapy is associated with several severe extra-hepatic side effects and the most common adverse events are hematological abnormalities and thyroid disorders and they could result in dose reduction and/or termination of therapy. Vitamin D has been shown to be a key regulatory element of the immune system, and its serum concentrations correlate with the severity of liver damage and the development of liver fibrosis/cirrhosis. Furthermore, supplementation with vitamin D with Peg-IFN-α based therapy for the treatment of CHC could be beneficial in increase the response rate to Peg-INF-α based therapy. Vitamin D has also been shown to regulate the thyroid functions and the process of erythropoiesis. This review appraises the data to date researching the role of vitamin D during the treatment of CHC and the potential role of vitamin D in preventing/treating Peg-IFN-α induced thyroiditis and anemia during the course of treatment.

Hepatitis C virus and interferon type III (interferon-λ3/interleukin-28B and interferon-λ4): genetic basis of susceptibility to infection and response to antiviral treatment

There has been a significant increase in our understanding of the host genetic determinants of susceptibility to viral infections in recent years. Recently, two single-nucleotide polymorphisms (SNPs), rs12979860 T/C and rs8099917 T/G, upstream of the interleukin (IL)-28B/interferon (IFN)-λ3 gene have been clearly associated with spontaneous and treatment-induced viral clearance in hepatitis C virus (HCV) infection. Because of their power in predicting the response to IFN/ribavirin therapy, the above SNPs have been used as a diagnostic tool, even though their relevance in the management of HCV infection will be blunt in the era of IFN-free regimens. The recent discovery of a new genetic variant, ss469415590 TT/ΔG, upstream of the IL-28B gene, which generates the novel IFN-λ4 protein, has opened up a new and alternative scenario to understand the functional architecture of type III IFN genomic regions and to improve our knowledge of the pathogenetic mechanism of HCV infection. A role of ss469415590 in predicting responsiveness to antiviral therapy has also been observed in HCV-infected patients receiving direct antiviral agents. The underlying biological mechanism that links the above IL-28B polymorphisms (in both IFN-λ3 and IFN-λ4) to spontaneous and treatment-induced clearance of HCV infection remains to be discovered. Despite this, shedding some light on this issue, which is the main aim of this review, may provide new insights into the general topic of 'host genetics and viral infections'.

Vitamin D pathway gene variants and HCV-2/3 therapy outcomes

BACKGROUND

The combination of ribavirin and pegylated interferon-α is considered the standard of care for HCV-2/3 genotypes. The immune system plays a key role in the achievement of a sustained virological response (SVR). Vitamin D seems to influence antiviral response in chronic hepatitis C and its pathway is controlled by polymorphic genes such as CYP27B1, CYP24A1 and VDR. In this study, we have investigated the correlation among the treatment outcomes and single nucleotide polymorphisms (SNPs) in the above-mentioned genes and IL28B genes.

METHODS

A total of 112 HCV-2/3 patients treated with interferon plus ribavirin were retrospectively studied; allelic discrimination was performed by real-time PCR.

RESULTS

CYP24A1rs2585428, IL28Brs12979860 and rs8099917 SNPs affected treatment failure and body mass index (BMI), Metavir score, IL28Brs8099917TT and CYP24A1rs2585428GG were the only factors able to predict it. SVR was predicted by Metavir score, HCV RNA at baseline and early virological response (EVR). IL28Brs12979860 SNP and HCV RNA were also related to rapid virological response. EVR was predicted by BMI, Metavir score and CYP24A1rs2585428 SNP. IL28Brs8099917TT and FokITT were relapse prediction factors.

CONCLUSIONS

In addition to non-genetic factors, SNPs in the vitamin D pathway seem to have a role in HCV-2/3 therapy outcomes. This study reveals the likely usefulness of pharmacogenetic-based ribavirin and interferon therapy to help identify patients for whom therapy could be successful or not, also considering new future expensive therapy options. To date, no similar data were published on these viral genotypes, but further studies in different and bigger cohorts are needed.

Significance of vitamin d receptor gene polymorphisms for risk of hepatocellular carcinoma in chronic hepatitis C

BACKGROUND/AIMS

Biological and epidemiological data suggest that vitamin D levels may influence cancer development. Several single nucleotide polymorphisms have been described in the vitamin D receptor (VDR) gene in association with cancer risk. We aimed to investigate the association of VDR gene polymorphisms with hepatocellular carcinoma (HCC) development in chronic hepatitis C patients.

METHODS

In a cross-sectional, hospital-based setting, 340 patients (201 chronic hepatitis, 47 cirrhosis and 92 HCC) and 100 healthy controls receiving VDR genotyping (bat-haplotype: BsmI rs1544410 C, ApaI rs7975232 C and TaqI rs731236 A) were enrolled.

RESULTS

Patients with HCC had a higher frequency of ApaI CC genotype (P = 0.027) and bAt[CCA]-haplotype (P = 0.037) as compared to control subjects. There were no differences in BsmI and TaqI polymorphisms between two groups. In patients with chronic hepatitis C, HCC subjects had a higher frequency of ApaI CC genotype and bAt[CCA]-haplotype than those with chronic hepatitis (P = 0.001 and 0.002, respectively) and cirrhosis (P = 0.019 and 0.026, respectively). After adjusting age and sex, logistic regression analysis showed that ApaI CC genotype (odds ratio: 3.02, 95% confident interval: 1.65-5.51) was independently associated with HCC development.

CONCLUSION

VDR ApaI polymorphism plays a role in the development of HCC among chronic hepatitis C patients. Further explorations of this finding and its implications are required.

Review article: genetic factors that modify the outcome of viral hepatitis

BACKGROUND

Genetic factors can play an important role for treatment response and disease progression in chronic viral hepatitis.

AIM

To review the influence of host genetic factors on the clinical course as well as on treatment response in patients with viral hepatitis.

METHODS

Review of the literature.

RESULTS

A landmark genome-wide association study (GWAS) identified polymorphisms in the IL28B gene on chromosome 19 (19q13.13) associated with response to therapy with pegylated interferon-α (PEG-IFN) and ribavirin (RBV) and spontaneous viral clearance in acute hepatitis C. Furthermore, IL28B genotype is associated with changes of lipid metabolism and insulin resistance. A further GWAS demonstrated that ITPA genetic variants protect HCV genotype 1 patients from RBV-induced anaemia. Another polymorphism in the patatin-like phospholipase domain containing 3 (PNPLA3) is associated with hepatic steatosis. Difficult-to-treat hepatitis C patients homozygous for GG had an up to five-fold lower chance of viral clearance on PEG/RBV than non-GG patients. In chronic hepatitis B patients treated with PEG-IFN several retrospective analyses of IL28B rs12980275 and rs12979860 genotypes yielded conflicting results which can be explained by the heterogeneity between the study populations. Some variants of the HLA-DP locus (HLA-DPA1 A allele and HLA-DPB1) protect against progression of chronic hepatitis B infection.

CONCLUSIONS

The determination of IL28B polymorphisms may be useful to individualise treatment options when using PEG/RBV based therapies for chronic hepatitis C infection. In contrast, so far identified genetic factors play only a minor role in chronic hepatitis B infection.