Quasispecies evolution in NS5A region of hepatitis C virus genotype 1b during interferon or combined interferon-ribavirin therapy

AIM: To evaluate the implication of substitutions in the hepatitis C virus (HCV) non-structural 5A (NS5A) protein in the resistance of HCV during mono-interferon (IFN) or combined IFN-ribavirin (IFN-R) therapy. Although NS5A has been reported to interact with the HCV RNA- dependent RNA polymerase, NS5B, as well as with many cellular proteins, the function of NS5A in the life cycle of HCV remains unclear. METHODS: HCV quasispecies were studied by clon- ing and sequencing of sequential isolates from patients infected by HCV genotype 1b. Patients were treated by IFN-α2b for 3 mo followed by IFN-α2b alone or com- bined IFN-R therapy for 9 additional months. Patients were categorized intro two groups based on their re- sponse to the treatments: 7 with sustained virological re- sponse (SVR) (quasispecies = 150) and 3 non-respond- ers (NR) to IFN-R (quasispecies = 106). RESULTS: Prior to treatment, SVR patients displayed a lower complexity of quasispecies than NR patients. Most patients had a decrease in the complexity of quasispe- cies during therapy. Analysis of amino acids substitu- tions showed that the degree of the complexity of the interferon sensitivity-determining region (ISDR) and the V3 domain of NS5A protein was able to discriminate thetwo groups of patients. Moreover, SVR patients displayed more variability in the NS5A region than NR patients. CONCLUSION: These results suggest that detailed mo- lecular analysis of the NS5A region may be important for understanding its function in IFN response during HCV 1b infection.

Mutations around interferon sensitivity-determining region:A pilot resistance report of hepatitis C virus 1b in a Hong Kong population

AIM： To explore mutations around the interferon sensitivity-determining region （ISDR） which are associated with the resistance of hepatitis C virus lb （HCV-lb） to interferon-α treatment. METHODS： Thirty-seven HCV-lb samples were obtained from Hong Kong patients who had completed the combined interferon-α/ribavirin treatment for more than one year with available response data. Nineteen of them were sustained virological responders, while 18 were non-responders. The amino acid sequences of the extended ISDR （eISDR） covering 64 amino acids upstream and 67 amino acids downstream from the previously reported ISDR were analyzed. RESULTS： One amino acid variation （I2268V, P = 0.023） was significantly correlated with treatment outcome in this pilot study with a limited number of patients, while two amino acid variations （R2260H, P = 0.05 and $2278T, P = 0.05） were weakly associated with treat- ment outcome. The extent of amino acid variations within the ISDR or eISDR was not correlated with treat- ment outcome as previously reported. CONCLUSION： Three amino acid mutations near but outside of ISDR may associate with interferon treatment resistance of HCV-lb patients in Hong Kong.

Hepatitis C virus infection down-regulates the expression of peroxisome proliferator-activated receptor a and carnitine palmitoyl acyl-CoA transferase 1A

AIM： To elucidate the role of the peroxisome proliferator-activated receptor α （PPARα） and its target gene camitine palmitoyl acyl-CoA transferase 2A （CPT1A） in the pathogenesis of hepatitis C virus （HCV） infection.METHODS： Liver samples were collected from the patients with chronic HCV infection and controls. HepG2 cells were transfected with vector pEF352neo carrying. Two independent clones （clone N3 and N4） stably expressing HCV core protein were analyzed. Total RNA was extracted from cells and liver tissues. PPARα and CPT1A mRNAs were quantified by real-time polymerase chain reaction （PCR） using SYBR Green Master. Total extracted proteins were separated by polyacrylamide gel electrophoresis, and electroblotted. Membranes were incubated with the anti-PPARα antibody, then with a swine anti-rabbit IgG conjugated to horseradish peroxidase for PPARα. Protein bands were revealed by an enhanced chemiluminescence reaction for PPARα. For immunohistochemical staining of PPARα, sections were incubated with the primary goat polyclonal antibody directed against PPARα at room temperature.RESULTS： Real-time PCR indicated that the PPARα level and expression level of CPT1A gene in hepatitis C patients lowered significantly as compared with the controls （1.8±2.8 vs 13±3.4, P = 0.0002; 1.1±1.5 vs 7.4±1, P = 0.004）. Western blot results showed that the level of PPARα protein in the livers of hepatitis C patients was lower than that in controls （2.3±0.3 vs 3.6±0.2, P = 0.009）. The immunohistochemical staining results in chronic hepatitis C patients indicated a decrease in PPARα staining in hepatocytes compared with those in the control livers. The in vitro studies found that in the N3 and N4 colon stably expressing HCV core protein, the PPARα mRNA levels were significantly lower than that in the controls.CONCLUSION： The impaired intrahepatic PPARα expression is associated with the pathogenic mechanism in hepatic injury during chronic HCV infection. HCV infection reduced the expression of PPARα and CPT1A at the level of not only mRNAs but also proteins. PPARα plays an important role in the pathogenesis of chronic HCV infection, but the impaired function of this nuclear receptor in HCV infection needs further studies.

Ribavirin contributes to eradicate hepatitis C virus through polarization of T helper 1/2 cell balance into T helper 1 dominance

The mechanism of action of ribavirin(RBV) as an immunomodulatory and antiviral agent and its clinical significance in the future treatment of patients with hepatitis C virus(HCV) infection are reviewed.RBV up-regulates type 1 and/or 2 cytokines to modulate the T helper(Th) 1/2 cell balance to Th1 dominance.Examination of co-stimulatory signaling indicated that RBV down-modulates inducible co-stimulator on Th cells,which contributes to differentiating na?ve Th cells into Th2 cells while reducing their interleukin-10 production.The effects on T-regulatory(Treg) cells were also investigated,and RBV inhibited the differentiation of na?ve Th cells into adaptive Treg cells by downmodulating forkhead box-P3.These findings indicate that RBV mainly down-regulates the activity of Th2 cells,resulting in the maintenance of Th1 activity that contributes to abrogating HCV-infected hepatocytes.Although an interferon-free treatment regimen exhibits almost the same efficacy without serious complications,regimens with RBV will be still be used because of their ability to facilitate the cellular immune response,which may contribute to reducing the development of hepatocellular carcinogenesis in patients infected with HCV.

Human leukocyte antigen class II DQB1*0301, DRB1*1101 alleles and spontaneous clearance of hepatitis C virus infection: A meta-analysis

AIM： To assess the associations of human leukocyte antigen （HI_A） class Ⅱ DQB1＊0301 and/or DRB1＊1101 allele with spontaneous hepatitis C virus （HCV） clearance by meta-analysis of individual dataset from all studies published till date. METHODS： To clarify the impact of HLA class Ⅱ polymorphisms on viral clearance, we performed a metaanalysis of the published data from 11 studies comparing the frequencies of DQB1＊0301 and DRB1＊1101 alleles in individuals with spontaneous resolution to those with persistent infection. As we identified the heterogeneity between studies, summary statistical data were calculated based on a random-effect model. RESULTS： Meta-analyses yielded summary estimatesodds ratio （OR） of 2.36 [95%CI （1.62, 3.43）, P〈0.00001] and 2.02 [95%CI （1.56, 2.62）, P〈0.00001] for the effects of DQB1＊0301 and DRB1＊1101 alleles on spontaneous clearance of HCV, respectively. CONCLUSION： These results support the hypothesis that specific HLA class Ⅱ alleles might influence the susceptibility or resistance to persistent HCV infection. Both DQB1＊0301 and DRB1＊1101 are protective alleles and present HCV epitopes more effectively to CD4^＋T lymphocytes than others, and subjects with these two alleles are at a lower risk of developing chronic HCV infection. Large, multi-ethnic confirmatory and welldesigned studies are needed to determine the host genetic determinants of HCV infection.

Analysis of hepatitis B virus preS1 variability and prevalence of the rs2296651 polymorphism in a Spanish population

AIM To determine the variability/conservation of the domain of hepatitis B virus(HBV) pre S1 region that interacts with sodium-taurocholate cotransporting polypeptide(hereafter, NTCP-interacting domain) and the prevalence of the rs2296651 polymorphism(S267 F, NTCP variant) in a Spanish population. METHODS Serum samples from 246 individuals were included and divided into 3 groups: patients with chronic HBV infection(CHB)(n = 41, 73% Caucasians), patients with resolved HBV infection(n = 100, 100% Caucasians) and an HBV-uninfected control group(n = 105, 100% Caucasians). Variability/conservation of the amino acid(aa) sequences of the NTCPinteracting domain,(aa 2-48 in viral genotype D) and a highly conserved pre S1 domain associated with virion morphogenesis(aa 92-103 in viral genotype D) were analyzed by next-generation sequencing and compared in 18 CHB patients with viremia > 4 log IU/mL. The rs2296651 polymorphism was determined in all individuals in all 3 groups using an in-house real-time PCR melting curve analysis.RESULTS The HBV pre S1 NTCP-interacting domain showed a high degree of conservation among the examined viral genomes especially between aa 9 and 21(in the genotype D consensus sequence). As compared with the virion morphogenesis domain, the NTCPinteracting domain had a smaller proportion of HBV genotype-unrelated changes comprising > 1% of the quasispecies(25.5% vs 31.8%), but a larger proportion of genotype-associated viral polymorphisms(34% vs 27.3%), according to consensus sequences from Gen Bank patterns of HBV genotypes A to H. Variation/conservation in both domains depended on viral genotype, with genotype C being the most highly conserved and genotype E the most variable(limited finding, only 2 genotype E included). Of note, proline residues were highly conserved in both domains, and serine residues showed changes only to threonine or tyrosine in the virion morphogenesis domain. The rs2296651 polymorphism was not detected in any participant.CONCLUSION In our CHB population, the NTCP-interacting domain was highly conserved, particularly the proline residues and essential amino acids related with the NTCP interaction, and the prevalence of rs2296651 was low/null.

Associations of content and gene polymorphism of macrophage inhibitory factor-1 and chronic hepatitis C virus infection

BACKGROUND The expression of macrophage inhibitory factor-1(MIC-1) is increased in peripheral blood of patients with chronic hepatitis and liver cirrhosis. However, whether MIC-1 gene polymorphism is correlated with relevant diseases is not yet reported.AIM To explore the correlation between gene polymorphism in MIC-1 exon region and chronic hepatitis C virus(HCV) infection.METHODS This case-control study enrolled 178 patients with chronic hepatitis C(CHC) in the case group, and 82 healthy subjects from the same region who had passed the screening examination comprised the control group. The genotypes of rs1059369 and rs1059519 loci in the MIC-1 gene exon were detected by DNA sequencing. Also, the MIC-1 level, liver function metrics, liver fibrosis metrics, and HCV RNA load were determined. Univariate analysis was used to compare the differences and correlations between the two groups with respect to these parameters. Multivariate logistic regression was used to analyze the independent relevant factors of CHC.RESULTS The plasma MIC-1 level in the CHC group was higher than that in the control group(P < 0.05), and it was significantly positively correlated with alanine aminotransferase, aspartate aminotransferase(AST), type III procollagen N-terminal peptide(known as PIIINP), type IV collagen, and HCV RNA(P < 0.05), whereas negatively correlated with total protein and albumin(P < 0.05). The genotype and allele frequency distribution at the rs1059519 locus differed between the two groups(P < 0.05). The allele frequency maintained significant difference after Bonferroni correction(Pc < 0.05). Logistic multiple regression showed that AST, PIIINP, MIC-1, and genotype GG at the rs1059519 locus were independent relevant factors of CHC(P < 0.05). Linkage disequilibrium(LD) was found between rs1059369 and rs1059519 loci, and significant difference was detected in the distribution of haplotype A-C between the CHC and control groups(P < 0.05). Meanwhile, we found the MIC-1 level trend to increase among rs1059519 genotypes(P = 0.006) and the level of MIC-1 in GG genotype to be significantly higher than CC genotype(P = 0.009, after Bonferroni correction).CONCLUSION Plasma MIC-1 level was increased in CHC patients and correlated with liver cell damage, liver fibrosis metrics, and viral load. The polymorphism at the MIC-1 gene rs1059519 locus was correlated with HCV infection, and associated with the plasma MIC-1 level. G allele and GG genotype may be an important susceptible factor for CHC.

Hepatitis C Virus non-structural 5A abrogates signal transducer and activator of transcription-1 nuclear translocation induced by IFN-α through dephosphorylation

AIM： To study the effect of Hepatitis C virus nonstructural 5A （HCV NSSA） on IFNα induced signal transducer and activator of transcription-1 （STAT1） phosphorylation and nuclear translocation.METHODS： Expression of STAT1 Tyr701 phosphorylation at different time points was confirmed by Western blot, and the time point when p-STAT1 expressed most, was taken as the IFN induction time for further studies. Immunocytochemistry was used to confirm the successful transient transfection of NS5A expression plasmid. Immunofluorescene was performed to observe if there was any difference in IFNα-induced STAT1 phosphorylation and nuclear translocation between HCV NSSA-expressed and non-HCV NSSA-expressed cells. Western blot was used to compare the phosphorylated STAT1 protein of the cells.RESULTS： Expression of HCV NS5A was found in the cytoplasm of pCNS5A-transfected Huh7 cells, but not in the PRC/ CMV transfected or non-transfected cells, STAT1 Tyr701 phosphorylation was found strongest in 30 min of IFN induction, STAT1 phosphorylation and nuclear import were much less in the presence of HCV NS5A protein in contrast to pRC/CMV-transfected and non-transfected cells under fluorescent microscopy, which was further confirmed by Western blot.CONCLUSION： HCV NSSA expression plasmid is successfully transfected into Huh7 cells and HCV NS5A protein is expressed in the cytoplasm of the cells. IFN-α is able to induce STAT1 phosphrylation and nuclear translocation, and this effect is inhibited by HCV NS5A protein, which might be another possible resistance mechanism to interferon alpha therapy.

A mutation of the start codon in the X region of hepatitis B virus DNA in a patient with non-B,non-C chronic hepatitis

There are cases of hepatitis involving occult hepatitis B virus(HBV)infection in which,even though the HB surface antigen(HBsAg)is negative,HBV-DNA is detected by a polymerase chain reaction(PCR).We con-ducted a sequence analysis of the entire HBV region in a case of non-B non-C chronic hepatitis in a 46-yearold female.A diagnosis of non-B non-C chronic hepatitis was made.Although HBV markers,such as HBs antibody(anti-HBs),anti-HBc,HBeAg and anti-HBe,were negative,HBV-DNA was positive.Nested PCR was performed to amplify the precore region of HBV-DNA and all remaining regions by long nested PCR.Sequence analysis of the two obtained bands was conducted by direct sequencing.Compared with the control strains,the ATG(Methionine)start codon in the X region had mut ated to GTG(Valine).It is assumed that a mutation at the start codon in the X region may be the reason why HBV markers are negative in some cases of hepatitis that involve occult HBV infection.

Hepatitis C virus/human T lymphotropic virus 1/2 coinfection:Regional burden and virological outcomes in people who inject drugs

This review analyses current data concerning co-infection with hepatitis C virus(HCV) and human T lymphotropic virus(HTLV)-1/2 in people who inject drugs(PWID), with a particular focus on disease burden and global implications for virological outcome. In addition, the available treatment options for HTLV-1/2 are summarized and the on-going and likely future research challenges are discussed. The data in this review was obtained from 34 articles on HCV/HTLV-1/2 co-infection in PWID retrieved from the Pub Med literature database and published between 1997 and 2015. Despite unavailable estimates of the burden of HCV/HTLV-1/2 co-infection in general, the epidemiologic constellation of HTLV-1/2 shows high incidence in PWID with history of migration, incarceration, and other blood-borne infectious diseases such as HCV or human immunodeficiency virus. The most recent research data strongly suggest that HTLV-1 co-infection can influence HCV viral load, HCV sustained virological response to α-interferon treatment, and HCV-related liver disease progression. In short, outcome of HCV infection is worse in the context of HTLV-1 co-infection, yet more studies are needed to gain accurate estimations of the burden of HCV/HTLV-1/2 co-infections. Moreover, in the current era of new direct-acting antiviral treatments for HCV and proven HTLV-1/2 treatment options, prospective clinical and treatment studies should be carried out, with particular focus on the PWID patient population, with the aim of improving virological outcomes.

Form confers function:Case of the 3'X region of the hepatitis C virus genome

At the 3' end of genomic hepatitis C virus(HCV) RNA there is a highly conserved untranslated region,the 3'X-tail,which forms part of the 3'UTR.This region plays key functions in regulation of critical processes of the viral life cycle.The 3'X region is essential for viral replication and infectivity.It is also responsible for regulation of switching between translation and transcription of the viral RNA.There is some evidence indicating the contribution of the 3'X region to the translation efficiency of the viral polyprotein and to the encapsidation process.Several different secondary structure models of the 3'X region,based on computer predictions and experimental structure probing,have been proposed.It is likely that the 3'X region adopts more than one structural form in infected cells and that a specific equilibrium between the various forms regulates several aspects of the viral life cycle.The most intriguing explanations of the structural heterogeneity problem of the 3'X region came with the discovery of its involvement in long-range RNA-RNA interactions and the potential for homodimer formation.This article summarizes current knowledge on the structure and function of the 3'X region of hepatitis C genomic RNA,reviews previous opinions,presents new hypotheses and summarizes the questions that still remain unanswered.

Retreatment of patients with treatment failure of directacting antivirals: Focus on hepatitis C virus genotype 1b

The recent development of direct-acting antiviral agents(DAAs) against hepatitis C virus(HCV) infection could lead to higher sustained virological response(SVR) rates, with shorter treatment durations and fewer adverse events compared with regimens that include interferon. However, a relatively small proportion of patients cannot achieve SVR in the first treatment, including DAAs with or without peginterferon and/or ribavirin. Although retreatment with a combination of DAAs should be conducted for these patients, it is more difficult to achieve SVR when retreating these patients because of resistance-associated substitutions(RASs) or treatment-emergent substitutions. In Japan, HCV genotype 1 b(GT1 b) is founded in 70% of HCVinfected individuals. In this minireview, we summarize the retreatment regimens and their SVR rates for HCV GT1 b. It is important to avoid drugs that target the regions targeted by initial drugs, but next-generation combinations of DAAs, such as sofosbuvir/velpatasvir/voxilaprevir for 12 wk or glecaprevir/pibrentasvir for 12 wk, are proposed to be potential solution for the HCV GT1 b-infected patients with treatment failure, mainly on a basis of targeting distinctive regions. Clinicians should follow the new information and resources for DAAs and select the proper combination of DAAs for the retreatment of HCV GT1 b-infected patients with treatment failure.

Comparative Assay of Hepatitis B and C Virus Infection Markers by Different Assay Kits^1

In order to compare sensitivity of EIA and RIA assay kits for hepatitis B and C virus (HBV and HCV, respectively) infection markers, 100 serum samples in total were collected form 50 adult women each in urban and rural areas in northeast China. The number of positive cases to the three infection markers on HBV (i.e., HBsAg +, anti HBs +, and anti HBc +) and the one on HCV (anti HCV +) were examined in two laboratories, i.e., in Laboratory A with EIA kits produced in China and in Laboratory B with RIA kits. HCV infection positivity (anti HCV +) was examined by EIA kits in both laboratories, but from different sources in and outside of China, respectively. The assay in Laboratory A gave 2 HBsAg + cases out of the 100 cases examined, whereas there were 9 positive cases in Laboratory B. In contrast, 19 cases were positive to anti HCV when examined in Laboratory A, and there were 3 cases in Laboratory B. Thus, the kits used in Laboratory A gave fewer HBsAg + and more anti HCV + cases than the kits used in Laboratory B. The prevalence of anti HBs + or anti HBc + and cases did not differ when assayed in the two laboratories with EIA and RIA kits, respectively. The agreement of positive and negative findings between the two sets of testing were 93%, 93%, 93%, 86% and 82% for HBsAg, anti HBs, anti HBc, HBV (i.e., either positive to anyone of the three markers or negative to all three markers), and anti HCV, respectively. The implication of the observation on epidemiology on HBV and HCV infection prevalence was discussed.

Programmed death-1/programmed death-L1 signaling pathway and its blockade in hepatitis C virus immunotherapy

Chronic hepatitis C virus(HCV) infection is a public health issue that often progresses to life-threatening complications, including liver cirrhosis, fibrosis, and hepatocellular carcinoma. Impaired immune responses to HCV are key features of chronic HCV infection. Therefore, intervention strategies usually involve enhancing the immune responses against HCV. Cytotoxic CD8+ T lymphocytes(CTLs) play a critical role in the control of HCV infection. However, their cytolytic function can be impaired by the expression of co-inhibitory molecules. Programmed death-1(PD-1) receptor and its ligand PD-L1 function in a T cell co-inhibitory pathway, which either blocks the function of CTLs or the differentiation of CD8+ T cells. During chronic HCV infection, the immune inhibitory receptor PD-1 is upregulated on dysfunctional HCV-specific CD8+ T cells. As such, blockade of the PD-1/PD-L1 pathway in these CD8+ T cells might restore their functional capabilities. Indeed, clinical trials using therapies to block this pathway have shown promise in the fostering of anti-HCV immunity. Understanding how chronic HCV infection induces upregulation of PD-1 on HCV specific T cells and how the PD-1/PD-L1 interaction develops HCV specific T cell dysfunction will accelerate the development of an efficacious prophylactic and therapeutic vaccination against chronic HCV infections, which will significantly improve HCV treatments and patient survival. In this review, we discuss the relationship between PD-1 expression and clinical responses and the potential use of PD-1 blockade for anti-HCV therapy.

Hepatitis C virus infection and type 1 and type 2 diabetes mellitus

Hepatitis C virus(HCV) infection and diabetes mellitus are two major public health problems that cause devastating health and financial burdens worldwide. Diabetes can be classified into two major types: type 1 diabetes mellitus(T1DM) and T2 DM. T2 DM is a common endocrine disorder that encompasses multifactorial mechanisms, and T1 DM is an immunologically mediated disease. Many epidemiological studies have shown an association between T2 DM and chronic hepatitis C(CHC) infection. The processes through which CHC is associated with T2 DM seem to involve direct viral effects, insulin resistance, proinflammatory cytokines, chemokines, and other immunemediated mechanisms. Few data have been reported on the association of CHC and T1 DM and reports on the potential association between T1 DM and acute HCV infection are even rarer. A small number of studies indicate that interferon-α therapy can stimulate pancreatic autoim-munity and in certain cases lead to the development of T1 DM. Diabetes and CHC have important interactions. Diabetic CHC patients have an increased risk of developing cirrhosis and hepatocellular carcinoma compared with nondiabetic CHC subjects. However, clinical trials on HCV-positive patients have reported improvements in glucose metabolism after antiviral treatment. Further studies are needed to improve prevention policies and to foster adequate and cost-effec-tive programmes for the surveillance and treatment of diabetic CHC patients.

Hepatitis B virus pre S1 deletion is related to viral replication increase and disease progression

AIM:To investigate the clinical implications of hepatitis B virus(HBV) pre S1 deletion.METHODS:We developed a fluorescence resonance energy transfer-based real-time polymerase chain reaction(RT-PCR) that can detect four genotypes(wild type, 15-bp, 18-bp and 21-bp deletion).The PCR method was used in two cohorts of Korean chronic HBV subjects with genotype C infections.Cohort Ⅰ included 292 chronic HBV subjects randomly selected from Cheju National University Hospital(Jeju, South Korea) or Seoul National University Hospital(Seoul, South Korea), and cohort Ⅱ included 90 consecutive chronic HBV carriers recruited from Konkuk University Hospital(Seoul, South Korea); the cohort Ⅱ patients did not have hepatocellular carcinoma or liver cirrhosis.RESULTS:The method proposed in this study identified 341 of 382 samples(89.3%).Deletion variants were identified in 100(29.3%) of the 341 detected samples.In both cohorts, the subjects with deletions had a significantly higher Hepatitis B virus e antigen(HBe Ag)-positive seroprevalence [cohort Ⅰ, wild(51.0%) vs deletion(75.0%), P < 0.001; cohort Ⅱ, wild(69.2%) vs deletion(92.9%), P = 0.002] and higher HBV DNA levels [cohort Ⅰ, wild(797.7 pg/m L) vs deletion(1678.9 pg/m L), P = 0.013; cohort Ⅱ, wild(8.3 × 108 copies/m L) vs deletion(2.2 × 109 copies/m L), P = 0.049], compared to subjects with wild type HBV.CONCLUSION:HBV genotype C pre S1 deletion may affect disease progression in chronic HBV subjects through an extended duration of HBe Ag seropositive status and increased HBV replications.

Impact of hepatitis C virus heterogeneity on interferon sensitivity:An overview

Hepatitis C virus(HCV)is a major cause of liver disease worldwide.HCV is able to evade host defense mechanisms,including both innate and acquired immune responses,to establish persistent infection,which results in a broad spectrum of pathogenicity,such as lipid and glucose metabolism disorders and hepatocellular carcinoma development.The HCV genome is characterized by a high degree of genetic diversity,which can be associated with viral sensitivity or resistance(reflected by different virological responses)to interferon(IFN)-based therapy.In this regard,it is of importance to note that polymorphisms in certain HCV genomic regions have shown a close correlation with treatment outcome.In particular,among the HCV proteins,the core and nonstructural proteins(NS)5A have been extensively studied for their correlation with responses to IFN-based treatment.This review aims to cover updated information on the impact of major HCV genetic factors,including HCV genotype,mutations in amino acids 70 and91 of the core protein and sequence heterogeneity in the IFN sensitivity-determining region and IFN/ribavirin resistance-determining region of NS5A,on virological responses to IFN-based therapy.

Metabolic syndrome does not affect sustained virologic response of direct-acting antivirals while hepatitis C clearance improves hemoglobin A1c

AIM To determine whether successful treatment with direc-tacting antivirals(DAA) is associated with improvements in hemoglobin A1 c(HbA1 c) and if type 2 diabetes mellitus(T2 DM) or metabolic syndrome affects sustained virologic response(SVR).METHODS We performed a retrospective analysis of all hepatitis C virus(HCV) patients at the VA Greater Los Angeles Healthcare System treated with varying DAA therapy between 2014-2016. Separate multivariable logistic regression was performed to determine predictors of HbA1 c decrease ≥ 0.5 after DAA treatment and predictors of SVR 12-wk post treatment(SVR12).RESULTS A total of 1068 patients were treated with DAA therapy between 2014-2016. The presence of T2 DM or metabolic syndrome did not adversely affect SVR12. 106 patients had both HCV and T2 DM. Within that cohort,patients who achieved SVR12 had lower mean HbA1 c pre treatment(7.35 vs 8.60,P = 0.02),and lower mean HbA1 c post-treatment compared to non-responders(6.55 vs 8.61,P = 0.01). The mean reduction in HbA1 c after treatment was greater for those who achieved SVR12 than for non-responders(0.79 vs 0.01,P = 0.03). In adjusted models,patients that achieved SVR12 were more likely to have a HbA1 c decrease of ≥ 0.5 than those that did not achieve SVR12(adjusted OR = 7.24,95%CI: 1.22-42.94). CONCLUSION In HCV patients with T2 DM,successful treatment with DAA was associated with a significant reduction in HbA1 c suggesting that DAA may have a role in improving insulin sensitivity. Furthermore,the presence of T2 DM or metabolic syndrome does not adversely affect SVR12 rates in patients treated with DAA.

Relevance of low viral load in haemodialysed patients with chronic hepatitis C virus infection

AIM: To identify predictors of sustained virological response in hemodialysed patients treated by PEGinterferon α for chronic hepatitis C, genotype 1.METHODS: The sustained virological response(SVR) rate, IL28 B genotype, IFNL4 genotype, initial viral load(IVL) and other pretreatment variables in 39 endstage renal disease patients(ESRD) on maintenance haemodialysis(HD) infected with hepatitis C virus(HCV), genotype 1b, were compared with a control group of 109 patients with normal kidney function treated within the same period. All the patients were treatment nave and had well compensated liver disease. The ESRD patients received 135 μg of PEGylated interferon α-2a(Peg IFN-α) weekly and a reduced dose of ribavirin(RBV) was administered to 23/39 patients with an initial haemoglobin level > 10 g/d L. Control group patients were given standard doses of Peg IFN-α and RBV. SVR was assessed as HCV RNA negativity 24 wk post-treatment. A t-test or ANOVA were used for comparisons of the means and a χ2 testcompared the frequencies.Logistic regression was used to determine significant predictors of SVR.Cutoff values for continuous variables were obtained from Receiver Operating Characteristic analysis.RESULTS:The distribution of IL28B rs12979860 CC,CT and TT genotypes in the ESRD group was 28.2%,64.1%and 7.7%,respectively,and 19.3%,62.4%and18.3%in the controls.The IFNL4 genotype was in almost absolute linkage disequlibrium with IL28B.The proportion of patients with a low IVL(<600000 IU/m L)was significantly higher in the ESRD group than in the controls(28/39,71.8%vs 51/109,46.8%,P=0.009),as was the proportion of patients with low IVL in IL28B CC carriers compared with non-CC carriers in the ESRD group(10/11,90.9%vs 18/28,64.3%,P=0.0035).This difference was not found in the controls(7/22,31.8%vs 44/87,50.6%,P=0.9).The overall SVR rate was 64.1%(25/39)in the ESRD group and 50.5%(55/109)in the control group(P=0.19).11/11(100%)and 19/22(86.4%)IL28B CC patients achieved SVR in the ESRD and control groups,respectively.A statistically significant association between SVR and IL28B and IFNL4 variants was found in both groups.The ESRD patients who achieved SVR showed the lowest IVL[median 21000,interquartile range(IQR):6000-23000IU/m L],compared with ESRD individuals without SVR(1680000,IQR:481000-6880000,P=0.001),controls with SVR(387000,IQR:111000-1253000)and controls without SVR(905000,IQR:451000-3020000).In ESRD,an IVL<600000 IU/m L was strongly associated with SVR:24/28(85.7%)patients who achieved SVR had viraemia below this threshold.CONCLUSION:Haemodialysis decreases the viral load,especially in IL28B CC genotype carriers.A low IVL was the strongest predictor of SVR in ESRD patients identified in multivariate analysis.