Evidence for separation of HCV subtype 1a into two distinct clades

Summary. The nucleotide sequence diversity present among hepatitis C virus (HCV) isolates allows rapid adjustment to exterior forces including host immunity and drug therapy. This viral response reflects a combination of a high rate of replication together with an error‐prone RNA‐dependent RNA polymerase, providing for the selection and proliferation of the viruses with the highest fitness. We examined HCV subtype 1a whole‐genome sequences to identify positions contributing to genotypic and phenotypic diversity. Phylogenetic tree reconstructions showed two distinct clades existing within the 1a subtype with each clade having a star‐like tree topology and lacking definite correlation between time or place of isolation and phylogeny. Identification of significant phylogenetically informative sites at the nucleotide level revealed positions not only contributing to clade differentiation, but which are located at or proximal to codons associated with resistance to protease inhibitors (NS3 Q41) or polymerase inhibitors (NS5B S368). Synonymous/nonsynonymous substitution mutation analyses revealed that the majority of nucleotide mutations yielded synonymous amino acids, indicating the presence of purifying selection pressure across the polyprotein with pockets of positive selection also being detected. Despite evidence for divergence at several loci, certain 1a characteristics were preserved including the length of the alternative reading frame/F protein (ARF/F) gene, and a subtype 1a‐specific phosphorylation site in NS5A (S349). Our analysis suggests that there may be strain‐specific differences in the development of antiviral resistance to viruses infecting patients who are dependent on the genetic variation separating these two clades.     

Relationship between interferon therapy and variability in nonstructural gene 5b of hepatitis C virus

The hepatitis C virus (HCV) quasispecies nature in the hypervariable region (HVR) has been reported and found to relate to the effectiveness of interferon (IFN) treatment. However, the quasispecies nature in the nonstructural (NS) 5b region remains to be addressed. To examine this characterization and relationship with IFN therapy, we sequenced six independent HCV clones from each of eight patients. The eight patients were classified as responders or nonresponders to IFN. In the four responders, we found one to three isolates in each of the six clones. In the nonresponders, the six clones consisted of four, five, six, and six isolates, respectively. Compared the (NS) 5b genes of the isolates obtained from the patients with that of the reported hepatitis C virus HC-C2 or HC-J6 isolate the ratio of nonsynonymous to total substitutions ranged from 17.61% to 30.95% in the responders and from 33.11% to 76.47% in the nonresponders. We also compared posttreatment with pretreatment sequences. The average number of varying amino acids ranged from 5.5 to 9.0 in isolates remaining after IFN treatment and from 4.3 to 5.5 in the isolates that disappeared with IFN treatment. Two changed amino acids (glycine to arginine and valine to isoleucine) (compared with the pretreatment clones) were found in the posttreatment clones of one of the responders and one amino acid change (valine to alanine) was found in another responder. These results suggest that the NS5b quasispecies correlates with IFN treatment effectiveness. These results also implied that the heterogeneity in different hierarchical strata has a common impact on IFN treatment, making infected patients resistant to IFN. Our study also provides evidence that HCV elimination and mutation may occur simultaneously during IFN therapy. Received Sept. 19, 1997; accepted Feb. 27, 1998     

Induction of interferon‐λ contributes to Toll‐like receptor‐3‐activated hepatic stellate cell–mediated hepatitis C virus inhibition in hepatocytes

There is limited information about the role of hepatic stellate cells (HSC) in liver innate immunity against hepatitis C virus (HCV). We thus examined whether HSC can produce antiviral factors that inhibit HCV replication in human hepatocytes. HSC expressed functional Toll‐like receptor 3 (TLR‐3), which could be activated by its ligand, polyinosine‐polycytidylic acid (poly I:C), leading to the induction of interferon‐λ (IFN‐λ) at both mRNA and protein levels. TLR‐3 signalling of HSC also induced the expression of IFN regulatory factor 7 (IRF‐7), a key regulator of IFN signalling pathway. When HCV JFH‐1‐infected Huh7 cells were co‐cultured with HSC activated with poly I:C or incubated in media conditioned with supernatant (SN) from poly I:C‐activated HSC, HCV replication was significantly suppressed. This HSC SN action on HCV inhibition was mediated through IFN‐λ, which was evidenced by the observation that antibody to IFN‐λ receptors could neutralize the HSC‐mediated anti‐HCV effect. The role of IFN‐λ in HSC‐mediated anti‐HCV activity is further supported by the observation that HSC SN treatment induced the expression of IRF‐7 and IFN‐stimulated genes (ISGs), OAS‐1 and MxA in HCV‐infected Huh7 cells. These observations indicate that HSC may be a key regulatory bystander, participating in liver innate immunity against HCV infection using an IFN‐λ‐dependent mechanism.     

Effect of TT virus co‐infection on interferon response in chronic hepatitis C patients

Abstract: Aim: TT virus (TTV) is a single stranded DNA virus found in serum of patients with post‐transfusion non‐A to ‐G hepatitis. TTV‐DNA has been investigated in sera of patients with various liver diseases. This study aimed at finding whether co‐infection with TTV in HCV patients, may influence the effect of interferon (IFN) in complete elimination of HCV, and analysed the correlation between HCV and TTV by semi‐quantification of both HCV RNAs and TTV DNA. Methods: In 28 chronic hepatitis C (CH‐C) patients with TTV co‐infection, the presence of TTV DNA was checked in sera six months before and after the end of IFN therapy. Result: Five out of 28 patients became negative for both HCV‐RNA and TTV‐DNA following IFN therapy. But 10 out of 28 patients persistently remained positive for both. Among the remaining 13 patients, 5 tested negative for HCV‐RNA but positive for TTV‐DNA. Post IFN therapy changes in serum alanine aminotransferase (ALT) levels did not appear to be influenced by the presence of TTV co‐infection. HCV‐RNA was found to be the most important predictor of IFN response in CH‐C patients with TTV co‐infection. TTV DNA level in sera had no correlation with IFN response. In addition, there was no relationship between HCV RNA and TTV DNA. Conclusion: Based on these results, it can be concluded that the effectiveness of IFN in eliminating HCV does not seem to be influenced by co‐infection.     

Urgency to treat patients with chronic hepatitis C in Asia

Chronic hepatitis C (CHC) infection poses a global healthcare burden, being associated with serious complications if untreated. The prevalence of hepatitis C virus (HCV) infection is highest in areas of Central, South, and East Asia; over 50% of HCV patients worldwide live in the region, where HCV genotypes 1b, 2, 3, and 6 are the most prevalent. Treatment outcomes for chronic hepatitis C vary by ethnicity, and Asian patients achieve higher sustained virologic response rates following interferon (IFN)‐based therapy than non‐Asians. However, low efficacy, poor safety profile, and subcutaneous administration limit the use of IFN‐based therapies. Superior virologic outcomes have been observed with different classes of direct‐acting antivirals (DAAs) alone or in combination, and several all‐oral DAA regimens are available in Asia. These regimens have shown excellent efficacy and favorable tolerability in clinical trials, yet there is a need for further studies of DAAs in a real world context, particularly in Asia. Furthermore, IFN‐free treatment may not be accessible for many patients in the region, and IFN‐based regimens remain an option in some countries. There is a need to improve current clinical practices for HCV management in Asia, including effective screening, disease awareness, and prevention programs, and to further understand the cost‐effectiveness of IFN‐free regimens. The evolution of potent treatments makes HCV eradication a possibility that should be available to all patients. However, access to these therapies in Asian countries has been slow, primarily because of economic barriers that continue to present a hurdle to optimal treatment.     

Long‐term clearance of hepatitis C virus following interferon α‐2b or peginterferon α‐2b,alone or in combination with ribavirin

Sustained virologic response (SVR) is the standard measure for evaluating response to therapy in patients with chronic hepatitis C (CHC). The aim of this study was to prospectively assess the durability of SVR in the pivotal studies of peginterferon (PEG‐IFN) α‐2b or IFN α‐2b. We conducted two phase 3b long‐term follow‐up studies of patients previously treated for CHC in eight prospective randomized studies of IFN α‐2b and/or PEG‐IFN α‐2b. Patients who achieved SVR [undetectable hepatitis C virus (HCV) RNA 24 weeks after completion of treatment] were eligible for inclusion in these follow‐up studies. In total, 636 patients with SVR following treatment with IFN α‐2b and 366 with SVR following treatment with PEG‐IFN α‐2b were enrolled. Definite relapse (quantifiable serum HCV RNA with no subsequent undetectable HCV RNA) was reported in six patients treated with IFN α‐2b and three patients treated with PEG‐IFN α‐2b. Based on these relapses, the point estimate for the likelihood of maintaining response after 5 years was 99.2% [95% confidence interval (CI), 98.1–99.7%] for IFN α‐2b and 99.4% (95% CI, 97.7–99.9%) for PEG‐IFN α‐2b. Successful treatment of hepatitis C with PEG‐IFN α‐2b or IFN α‐2b leads to clinical cure of hepatitis C in the vast majority of cases.     

Augmentation of hepatitis C virus‐specific immunity and sustained virologic response

Treatment for chronic hepatitis C virus (HCV) infection has rapidly evolved into interferon‐free directly acting antiviral regimens (DAA) that result in high sustained virologic response. DAAs primarily work by suppressing HCV replication and rely less on the immune system than interferon‐based therapies. However, it is unclear whether the immune system recovers with suppression of HCV replication and contributes to HCV clearance with DAA therapy. We previously demonstrated HCV clearance is associated with increased HCV‐specific immunity in CHCV‐GT‐1‐infected patients during treatment with sofosbuvir (SOF)+ribavirin (RBV). Here, we aimed to analyse changes in HCV‐specific immunological responses associated with viral clearance with combination DAA therapy of SOF+ledipasvir (LDV) for 12 weeks in CHCV‐GT1 (N=14) patients who relapsed without augmentation of HCV‐specific immunity during treatment with SOF+RBV. Phenotypic and functional changes within the T‐cell compartment of PBMCs pre‐ and post‐treatment were analysed. Retreatment of relapsers with LDV/SOF resulted in all patients attaining SVR₁₂. Suppression of HCV was associated with a decline in T‐cell exhaustion markers (CD57; Tim3; PD1) along with augmented of HCV‐specific T‐cell IFN‐gamma responses post‐treatment. Addition of LDV to SOF was associated with augmentation of HCV‐specific immunity and SVR in patients who previously failed SOF+RBV therapy without increased immunity. These findings demonstrate a novel effect of DAA in inducing host immune responses to aid HCV clearance and achieve SVR.     

Integrity of the NS5A (amino acid 2209 to 2248) region in hepatitis C virus 1b patients non‐responsive to interferon therapy

Abstract: Background/Aims: In hepatitis C virus‐1b, it has been suggested that an amino acid stretch (aa 2209–2248) of the carboxy terminal half of the non‐structural 5A (NS5A) region participates in the response to interferon treatment. We tested the hypothesis that absence of mutations in the NS5A (aa 2209–2248) sequence is required for interferon resistance. We also investigated the importance of different HCV‐1b isolates in interferon response in France. Methods: We determined the NS5A sequences of 70 patients with chronic hepatitis C before IFN therapy and then compared them with HCV‐J prototype sequence. The isolates were determined by NS5B sequencing, the “gold standard” method for genotyping and subtyping. Pre‐therapeutic viral load was also measured. Results: No sustained virological response was observed in the patients without amino acid substitutions in the NS5A (aa 2209–2248) sequence, and in the patients with HCV‐J isolates. Viral load was significantly higher in the patients with no amino acid substitutions in the NS5A (aa 2209–2248) sequence. Conclusions: In HCV‐1b infected patients, an HCV‐J strain with no amino acid substitution in the NS5A (aa 2209–2248) region indicates a poor prognosis for response to IFN therapy. The low interferon response rate in HCV‐1b infection in Europe is probably not due to a difference between isolates.     

Influenza Classification Suite: An automated Galaxy workflow for rapid influenza sequence analysis

Influenza viruses continually evolve to evade population immunity, and the different lineages are assigned into clades based on shared mutations. We have developed a publicly available computational workflow, the Influenza Classification Suite, for rapid clade mapping of sequenced influenza viruses. This suite provides a user‐friendly workflow implemented in Galaxy to automate clade calling and antigenic site extraction. Workflow input includes clade definition and amino acid index array files, which can be customized to identify any clades of interest. The Influenza Classification Suite provides rapid, high‐resolution understanding of circulating influenza strain evolution to inform influenza vaccine effectiveness and the need for potential vaccine reformulation.     

Prospective study of short-term peginterferon-alpha-2a monotherapy in patients who had a virological response at 2 weeks after initiation of interferon therapy

Background and Aims: Long‐term interferon (IFN) therapy is effective in eliminating hepatitis C virus (HCV). However, it carries the risk of adverse effects and reduced quality of life. To assess whether short‐term IFN therapy effectively eliminates HCV, we performed a prospective pilot study of pegylated (peg)IFN‐α‐2a therapy for 8 or 24 weeks. Methods: After excluding patients with high titers of genotype‐1, 55 HCV patients received pegIFN‐α‐2a. Patients who became negative for HCV‐RNA at week 2 were allocated to either an 8‐week (n = 19) or 24‐week (n = 15) course of IFN. We evaluated the efficacy of and tolerance to IFN therapy. Results: The sustained virological response rate was excellent in the two groups (8 weeks, 89.5% [17/19]; 24 weeks, 100% [15/15], respectively,). IFN dose reduction was required in one patient of the 8‐week group, but in six patients of the 24‐week group (P = 0.028). Treatment was completed by all patients of the 8‐week group, but discontinued in five patients of the 24‐week group (P = 0.011). Conclusions: The 8‐week IFN therapy is more tolerable than the 24‐week therapy and had similar outcomes. Excluding the patients with high titers of genotype‐1, we recommend switching to an 8‐week course of pegIFN‐α monotherapy once patients show an ultra rapid virological response at week 2 from the start of IFN therapy.     

High sustained response to daily dosing of interferon with ribavirin in chronic hepatitis C patients naïve to therapy

Background : Viral kinetics suggests that daily administration of α‐interferon (IFN) will clear hepatitis C virus (HCV) RNA earlier and more frequently compared with standard t.i.w. To reduce the likelihood of viral replication, mutation and subsequent development of resistance, daily dosing with IFN may be appropriate. To determine the safety and efficacy of daily IFN with ribavirin in chronic HCV infection we performed a prospective study. Methods : Thirty‐five naïve adult HCV‐positive patients (25 male/10 female) were treated with IFN‐α2b; 5 MU daily for 2 weeks followed by 3 MU daily for 22 weeks and ribavirin 800–1200 mg/day depending on weight. Liver biopsy, performed in 25 patients, showed mild to moderate activity in 19 patients (76%) and severe activity in six patients (24%). Two patients showed staged IV fibrosis. Serotyping was performed in 29 patients by an enzyme immunoassay‐based Murex assay. Type 3 was the predominant serotype, present in 14 cases. Hepatitis C virus RNA was measured by the Chiron bDNA assay. Results : Mean baseline HCV‐RNA level was 14.2 ± 18.7 MEq/mL (median 6.09; range 0.2–92.5), which became undetectable in all but three patients at week 4. Normalization of alanine aminotransferase (ALT) at week 4 was seen in 27 patients. Three patients withdrew due to non‐compliance. Thirty‐two patients completed 24 weeks of therapy as per the protocol. At the end of treatment, the HCV‐RNA level was negative in 29 of 32 patients (90.6%) and ALT was normal in 31 of 32 patients (97%). Sustained viral response at 6 months follow up was seen in 28 of 32 patients (88%). The ALT level was normal in 28 of 32 patients (88%). Conclusion : Daily administration of IFN with ribavirin is well tolerated in the majority of patients. There is rapid elimination of virus with normalization of ALT and a significantly high sustained viral response. © 2002 Blackwell Publishing Asia Pty Ltd     

Association between HCV amino acid substitutions and outcome of peginterferon and ribavirin combination therapy in HCV genotype 1b and high viral load

Background and Aim: We prospectively compared the sensitivity to interferon (IFN) and the efficacy of antiviral combination therapy with peginterferon (PEG‐IFN) and ribavirin for chronic hepatitis C virus (HCV) genotype 1b infection according to the amino acid sequences of the HCV core, E1, and NS5A regions reported to be associated with the outcome of antiviral therapy. Methods: A total of 107 patients with HCV genotype 1b were investigated. All patients received combination therapy with PEG‐IFN alpha‐2b and ribavirin. Amino acids 70 and 91 (core), 139 (E1), and 2209–2248 (NS5A) of HCV were analyzed by direct nucleotide sequencing. Results: The reduction in HCV RNA concentration at 24 h after a single administration of conventional IFN‐alpha and after the start of combination therapy was significantly less marked, and rates of complete early virologic response, end‐of‐treatment response, and sustained virologic response (SVR) were significantly lower (all P < 0.0001) in patients with glutamine at amino acid 70 (n = 29) than in those with arginine at that position (n = 70). We found no differences associated with the other amino acid positions. Amino acid 70 was an independent factor for the responses to the therapy in multivariate analysis. Conclusion: The identity of amino acid 70 of the HCV core region affected the sensitivity to IFN; patients with glutamine at amino acid 70 of HCV showed resistance to IFN. Consequently, it strongly affected the outcome of combination therapy with PEG‐IFN and ribavirin in Japanese patients with HCV genotype 1b.     

Mutations in the NS5A and E2‐PePHD regions of hepatitis C virus genotype 1b and response to combination therapy of interferon plus ribavirin

Background/aims: Combination therapy with interferon (IFN) and ribavirin is the current standard treatment for chronic hepatitis C, but the efficacy is still not satisfactory, especially for genotype 1b. NS5A and E2 proteins of hepatitis C virus (HCV) may repress the IFN‐induced RNA‐dependent protein kinase (PKR), and thus have the potential to influence the response of HCV to IFN therapy; however, this issue remains controversial. Methods: Nucleotide sequences of the PKR‐eIF2α phosphorylation homology domain (E2‐PePHD) and PKR‐binding domain (NS5A‐PKR bd) of the HCV genome were analyzed by amplification and direct sequencing in 30 HCV genotype 1b patients who had been treated with IFN and ribavirin. Results: Nine (30%) patients achieved a sustained virological response (SVR) to combination therapy. Pretreatment variables and amino acid substitutions were compared between responders and non‐responders. The responders were younger than non‐responders (37.2±10.4 vs. 45.4±9.5 years, P=0.017), whereas no significant statistical differences were found in the number of amino acid substitutions in NS5A and E2‐PePHD regions between the two groups. Conclusions: Genetic heterogeneity in NS5A and E2‐PePHD regions of the HCV genome may not serve as a predictor for treatment outcome with combination therapy in Taiwanese patients with chronic HCV genotype 1b infection.     

Multicenter Study of Pegylated Interferon α‐2a Monotherapy for Hepatitis C Virus‐Infected Patients on Hemodialysis: REACH Study

Many studies have reported poor vital prognosis in hepatitis C virus (HCV)‐infected dialysis patients. The rate of HCV‐infected dialysis patients in Japan is as high as 9.8%, and antiviral therapy is believed to be important for improving vital prognosis. We conducted a multicenter study to examine the administration method for pegylated interferon α‐2a (PEG‐IFNα‐2a) monotherapy in HCV‐infected dialysis. We studied 56 patients: 14 with low viral loads (HCV RNA < 5.0 log IU/mL) were treated with 90 μg PEG‐IFNα‐2a weekly, 42 with high viral loads (HCV RNA ≥ 5.0 log IU/mL) were treated with 135 μg PEG‐IFNα‐2a weekly. We examined the sustained virological response (SVR), factors affecting the SVR, and treatment safety. The overall SVR rate was 39% (22/56); that for genotype 1, genotype 2, low viral loads, and high viral loads was 29%, 67%, 93%, and 21%, respectively. From receiver operating characteristic (ROC) analysis, the HCV RNA cutoff values likely to achieve SVR for genotypes 1 and 2 were <5.7 log IU/mL (SVR rate: 64% 9/14) and <6.5 log IU/mL (SVR rate: 88% 7/8), respectively. If there was HCV RNA negativation at 4 weeks (rapid virological response), the SVR rate was 94% (16/17), whereas it was 6% (1/16) if there was HCV RNA positivity at 24 weeks. The rate of treatment discontinuation from adverse events or aggravated complications was 25% (14/56). High SVR rates can potentially be achieved with PEG‐IFN monotherapy by identifying the target patients, based on virus type and viral load before initiating treatment and by modifying therapy during treatment according to responsiveness.     

Efficacy and safety of pegylated interferon alpha‐2a therapy for chronic hepatitis C in HIV‐infected patients with haemophilia

Summary. The objective of this study was to evaluate the efficacy and safety of pegylated interferon (PEG‐IFN) alpha‐2a monotherapy in a cohort of Chinese haemophilic patients co‐infected with human immunodeficiency virus (HIV)/hepatitis C virus (HCV) and undergoing highly active antiretroviral drugs therapy. Twenty‐two (n = 22) patients with CD4 lymphocyte counts over 200 cells μL^?1 were treated with 180 μg of PEG‐IFN alpha‐2a subcutaneously once in a week for 48 weeks. HCV load (HCV RNA), HIV load (HIV RNA) and CD4 lymphocyte counts were measured at baseline and 4, 12, 24, 48 and 72 weeks after initiation of anti‐HCV therapy. Efficacy and safety were analysed according to baseline CD4 status (≥350 cells μL^?1). Significant HCV‐RNA decreases (>1 log₁₀ copies mL^?1) were observed through week 72 after PEG‐INF alpha‐2a monotherapy across both CD4 strata. CD4 status was not associated with treatment outcomes as evaluated using rapid viral response rate (P = 0.655), early viral response rate (P = 0.387), end‐of‐treatment viral response rate (P = 1.000) or sustained viral response rate (SVR, P = 0.674). A sustained virological response was achieved in nine patients (41%), five with genotype 2a (83%) and four with genotype 1b (25%, P = 0.023). SVR was HCV genotype dependent. Eleven patients required a dose reduction in PEG‐IFN alpha‐2a. PEG‐IFN alpha‐2a monotherapy could be considered as a safe and effective option for the treatment of HCV infection in HIV patients with haemophilia, particularly in resource‐limited settings. While higher CD4 lymphocyte counts resulted in greater HCV‐RNA reduction, HCV genotype was a predictor for sustained virological response.     

A Phylogeographic Investigation of African Monkeypox

Monkeypox is a zoonotic disease caused by a virus member of the genus Orthopoxvirus and is endemic to Central and Western African countries. Previous work has identified two geographically disjuct clades of monkeypox virus based on the analysis of a few genomes coupled with epidemiological and clinical analyses; however, environmental and geographic causes of this differentiation have not been explored. Here, we expand previous phylogenetic studies by analyzing a larger set of monkeypox virus genomes originating throughout Sub-Saharan Africa to identify possible biogeographic barriers associated with genetic differentiation; and projected ecological niche models onto environmental conditions at three periods in the past to explore the potential role of climate oscillations in the evolution of the two primary clades. Analyses supported the separation of the Congo Basin and West Africa clades; the Congo Basin clade shows much shorter branches, which likely indicate a more recent diversification of isolates within this clade. The area between the Sanaga and Cross Rivers divides the two clades and the Dahomey Gap seems to have also served as a barrier within the West African clade. Contraction of areas with suitable environments for monkeypox virus during the Last Glacial Maximum, suggests that the Congo Basin clade of monkeypox virus experienced a severe bottleneck and has since expanded its geographic range.     

Tamoxifen alleviates hepatitis C virus‐induced inhibition of both toll‐like receptor 7 and JAK‐STAT signalling pathways in PBMCs of infected Egyptian females

Summary. Hepatitis C virus (HCV) is a major health concern in Egypt being highly prevalent among Egyptians. The two genders experience different responses to HCV infection and show variations in response to interferon (IFN)‐based therapy that may be attributed to sex hormones. We previously demonstrated the suppressive effect of 17β‐estradiol (E2) on the expression of the IFN‐stimulated gene MxA in HCV‐infected peripheral blood mononuclear cells (PBMCs). The selective oestrogen receptor (ER) modulator Tamoxifen has been shown to have an antiviral effect against HCV, but its effect on the host immune response is unknown. We investigated the effect of Tamoxifen on the IFN signalling pathways in PBMCs of HCV‐infected Egyptian females. We pooled PBMCs and treated then with exogenous interferon alpha (IFNα) or the TLR7 ligand, Imiquimod, and quantified the relative expressions of MxA using RTqPCR. Studies were performed with and without Tamoxifen pretreatment. Pretreatment with Tamoxifen reversed the suppressive effect of E2 on the JAK‐STAT pathway in IFNα‐treated PBMCs as indicated by a significant increase in MxA expression (P = 0.05*). Tamoxifen pretreatment also significantly upregulated MxA expression in Imiquimod‐treated PBMCs (P = 0.0011**), an effect not ascribed to ER blocking nor to an upregulation in TLR7 expression because Tamoxifen showed no potentiating effect on the expression of the receptor. In conclusion, our findings reveal that Tamoxifen has immunomodulatory effects whereby it enhances the host IFN signalling pathways during HCV infection.     

Correlates and characteristics of hepatitis C virus‐specific T‐cell immunity in exposed uninfected high‐risk prison inmates

Some hepatitis C (HCV)‐uninfected, high‐risk individuals have HCV‐specific cellular immunity without viraemia or seroconversion. The characteristics of these responses and the risk behavioural associations were studied in 94 subjects in a prospective cohort of recently seronegative prisoners reporting injecting drug use (IDU). Detailed behavioural data were collected. HCV antibody and PCR testing were performed. ELISpot assays for HCV‐induced interferon (IFN)‐γ and interleukin (IL)‐2 production by T lymphocytes, as well as multiplex in vitro cytokine production assays, were performed. Seventy‐eight subjects remained antibody and PCR negative and 16 seroconverted. Of the seronegative group, 22 (28%) had IFN‐γ ELISpot responses in comparison with 13 of the 16 seroconverters (82%). This seronegative immune status was associated positively with injecting anabolic steroids and negatively with a recent break from IDU. The IFN‐γ ELISpot responses involved both CD4 and CD8 T lymphocytes and were comparable in magnitude, but narrower in specificity, in uninfected subjects than in seroconverters. A subset of seronegative subjects had HCV‐induced cytokine production patterns comparable with the seroconverters with increased production of IFN‐γ, IL‐2 and tumour necrosis factor (TNF)‐α and reduced IL‐10 in response to nonstructural peptides. In conclusion, comparable patterns of HCV‐specific cellular immunity are found in recently infected subjects and in a minority of high‐risk, uninfected subjects. Further characterization of these responses and their protective efficacy will inform HCV vaccine development.