Effect of mutation in the hepatitis C virus nonstructural 5B region on HCV replication

Background We have reported that the presence of a mutation at the hepatitis C virus (HCV) nonstructural protein 5B (NS5B), defined as a change in amino acids at sites specific for a different reported genotype, was related to complete response (CR) to interferon (IFN) therapy in patients with chronic hepatitis C (CHC) with genotype 1b. The present study assessed the impact of the NS5B mutation on the replication of HCV in these patients.Methods Genotype-specific mutations of HCV NS5B were determined by direct sequencing. We measured HCV-RNA titers in serum by real-time detected polymerase chain reaction (PCR), and serum HCV core protein levels (as a marker of HCV-RNA replication) were measured using an enzyme immunoassay in patients with CHC genotype 1b. RNA-dependent RNA polymerase (RdRp) activity was measured by Behrens method in liver cirrhosis patients infected with HCV (n = 13) and in those infected with hepatitis B virus (HBV; n = 2).Results The titers of HCV-RNA (n = 44) and the levels of HCV core protein (n = 41) were significantly lower in patients with the HCV genotype 1b mutant compared with wild-type HCV (P < 0.05). RdRp activity in liver tissue did not show any correlation with the HCV NS5B mutation.Conclusions HCV NS5B genotype-specific mutations in HCV genotype 1b may influence HCV replication.     

Response to interferon in chronic hepatitis C due to mixed genotype infection

We examined the response to interferon (IFN) in patients with chronic hepatitis C (CHC) due to two different genotypes of hepatitis C virus (HCV) infection. Among 64 CHC patients studied, one (2%) had HCV-RNA genotype I, 36 (56%) had genotype II, 19 (30%) had genotype III, 2 (3%) had genotype IV and 6 (9%) had both genotypes II and III. There was no significant difference in age, sex, history of blood transfusion and liver histology among patients with genotypes II, III and II + III. The HCV-RNA titre of genotype II patients was significantly higher than that of genotype III patients (P < 0.05). However, there was no significant difference in the HCV-RNA titre between genotype II + III and the other groups. The complete response rate achieved with IFN therapy was significantly higher in genotype III patients (74%) than in genotype II patients (17%; P < 0.01). Of the six patients with genotype II + III, a complete response to IFN was only achieved by two patients (33%), both of whom had a low HCV-RNA titre (≦ 10^4,5 copies/mL) and HCV serotype 2. The remaining four patients had HCV serotype 1 and three of the patients had a high HCV-RNA titre (≧ 10⁵ copies/mL). The HCV genotype III was lost in two patients after IFN therapy. These data suggest that HCV-RNA titre and HCV serotype are important factors for predicting the efficacy of IFN therapy in patients with mixed genotype infection and show direct evidence of higher susceptibility towards CHC of patients with genotype III than genotype II.     

Interferon therapy for patients more than 60 years of age with chronic hepatitis C

Abstract Nineteen patients aged > 60 years with chronic hepatitis C (CHC) received interferon (IFN) therapy and a complete response (CR) was achieved by five of them (26%). The incidence of CH with severe fibrosis in this elderly group was significantly higher than in another 52 patients with CHC who were < 60 years of age (the younger group; P < 0.05). There was no significant difference in the hepatitis C virus (HCV) genotype distribution between the elderly group and the younger group. However, the HCV-RNA titre was significantly higher in the elderly group than in the younger group ( P < 0.05). There was no significant difference in the efficacy rate of IFN in the elderly and younger groups after standardization of the background factors. In the elderly group, the HCV-RNA titre was significantly lower in the patients achieving CR than in those with no response ( P < 0.05). These data suggest that elderly patients with a low HCV-RNA titre can still respond well to IFN therapy.     

Sequence analysis of PePHD within HCV E2 region and correlation with resistance of interferon therapy in Japanese patients infected with HCV genotypes 2a and 2b

OBJECTIVE: Hepatitis C virus (HCV) E2 protein was recently reported to have a double-stranded RNA-activated protein kinase-eukaryotic initiation factor 2alpha (PKR-eIF2alpha) phosphorylation homology domain (PePHD); PKR is induced by interferon (IFN). PePHD interacts with PKR and inactivates it. PePHD could be a predictor for IFN response, like the interferon sensitivity determination region (ISDR) of HCV NS5A. Several groups reported that PePHD is conserved, and mutations in this region do not correlate with IFN response. In this study, we further investigated the amino acid variation of PePHD among four major genotypes and its correlation with IFN response. METHODS: We enrolled 74 patients for this study and determined PePHD sequence of HCV derived from sera of patients infected with HCV genotype 1a (1 patient; nonresponder [NR]), 1b (36 patients; 4 complete responders [CR], 32 NR), 2a (29 patients; 17 CR, 12 NR), and 2b (8 patients; 3 CR, 5 NR). We also analyzed mutations in ISDR of HCV genotype 1b in 31 patients. RESULTS: PePHD had several variations among four genotypes investigated. In patients infected with HCV genotype 1b, PePHD sequence was well conserved and seemed to have no correlation with IFN response. Mutations in ISDR were correlated with IFN response. In patients with HCV genotypes 2a and 2b, PePHD had multiple variations, and one particular motif, "RGQQ-" at the N-terminus, showed a close correlation with IFN resistance. All eight patients with HCV containing this motif were IFN nonresponders. CONCLUSIONS: IFN resistance of HCV correlates with its "RGQQ-" motif at the N-terminus of PePHD in HCV genotype 2a and 2b. PePHD of HCV could be a predictor of IFN resistance in patients infected with HCV genotype 2a and 2b.     

A health economic model to assess the long term effects and cost-effectiveness of PEG IFN alpha-2a in hepatitis C virus infected patients

OBJECTIVES: Chronic Hepatitis C (CHC) is associated with long-term complications. Treating CHC with Pegylated interferon alpha-2a (PEG IFN alpha-2a) improves response rates and may contribute to less morbidity and mortality compared to standard interferon therapy. The objectives of this study were to estimate the long-term clinical consequences of such treatment as well as the resulting cost-effectiveness. RESEARCH DESIGN AND METHODS: A Markov model was developed in order to predict the clinical and economic outcomes over a 25 year period. Three analyses were conducted: 1. for all Hepatitis C Virus (HCV) genotypes where PEG IFN alpha-2a was compared to interferon alpha-2a (IFN alpha-2a) in monotherapy for 48 weeks; 2. for the HCV genotypes 1-4-5-6 comparing PEG IFN alpha-2a with interferon alpha-2b (IFN alpha-2b) both combined with ribavirin 1000/1200 mg for 48 weeks; and 3, where PEG IFN alpha-2a with 800 mg ribavirin was compared to IFN alpha-2b with ribavirin 1000/1200 mg for 24 weeks in genotypes 2 and 3. RESULTS: In analysis one the cost-effectiveness of PEG IFN alpha-2a is 4,569/quality adjusted life year (QALY) gained. In the second analysis, the result was 14,763 euros/QALY, while for the 24 weeks therapy (analysis 3) the result was 903 per QALY gained. In an extensive sensitivity analysis cost-effectiveness was confirmed within reasonable assumptions. CONCLUSIONS: These results suggest that PEG IFN alpha-2a is cost-effective in the management of all CHC patients. Real life evidence about longer term benefits of PEG IFN alpha-2a will be of importance for future decision making.     

慢性丙型肝炎患者肝组织中病毒和Fas抗原表达及其与干扰素应答的关系

目的 探讨丙型肝炎患者肝组织中HCV Ns5和Fas抗原表达及其与肝组织损伤和干扰素治疗反应的关系.方法 应用a干扰素对一组慢性丙型肝炎患者进行24周治疗,停药后随访6个月,以血清丙氨酸转氨酶(ALT)恢复正常及血清HCV RNA持续阴转为完全应答标准,采用免疫组化方法检测组织中病毒和Fas抗原表达状况.结果 29例慢性丙型肝炎患者肝组织中,HCV NS5和Fas抗原呈阳性者均为19例(65.5%),两者在肝组织中的表达显著相关;单因素相关分析时,两者均与组织病变程度有关,但多因素分析表明只有HCV NS5抗原表达水平与组织炎症活动度呈正相关.治疗和随访结束时分别有17例(58.6%)和15例(51.7%)患者表现为近期和远期完全应答.治疗前Fas表达水平与干扰素应答有关,但未见HCV NS5水平与干扰素应答有明显关系;5例随访结束时重复肝穿,3例完全应答者病毒表达显著受抑,但Fas抗原无明显改变,2例无应答者病毒表达无明显改变甚或增强,而Fas表达均增强.结论 慢性丙型肝炎肝组织中HCV Ns5表达在慢性丙型肝炎发病过程中有重要意义;Fas抗原表达水平与组织中病毒表达相关;治疗前肝组织Fas表达状况与干扰素治疗反应有一定联系.     

Chronic hepatitis C in elderly patients: clinical, histological and virological features

Some clinical, histological and virological features, efficacy and safety of interferon (IFN) therapy were evaluated in elderly patients with chronic hepatitis C (CHC). We enrolled 22 patients aged 65-75 (mean age: 68.3 +/- 3.17 years); 15 males and 7 females. In all cases the hepatitis C virus RNA (HCV-RNA) was determined before, during and after the therapy, and HCV sub-types were established; 15 patients underwent hepatobiopsy. At entry, the duration of disease was: 6 patients 1-3 years, 2 patients 4-10 years, 14 patients 11-30 years; alanine-aminotransferase (ALT) = (3.17 +/- 1.15) x N (N = normal value); aspartate-transaminase (AST) = 2.28 +/- 1.6 x N; gamma-glutamyl-transpeptidase (gGT) = 1.4 +/- 1.1 x N; platelets = 164,000 +/- 66,000/mm(3); histological pattern: 2 mild chronic active hepatitis (CAH), 5 CAH, 2 severe CAM, 6 CAH with liver cirrhosis (LC); histological activity index (HAI) (14 patients) = 11.14 +/- 4.5 (range 5-17); scores according to Scheuer: lobular 2.28 +/- 1.13, portal 2.71 +/- 0.99, fibrosis 2.35 +/-1.33; HCV-RNA +ve: 20 patients, HCV-RNA -ve: 2 patients; HCV-subtypes: 1b 20/20 (100%), 1b+1a 1/20 (5%), 1b+ 2a 1/20 (5%). Treatment was applied to 18 patients, for 3-12 months; 5 received alpha-IFN2a; 5 received alpha-IFN2b, 3 lymphoblastoid IFN, all at a dose of 3 mU thrice per week; 3 patients received 6 mU beta-IFN thrice per week. Therapy over 6 months was applied to 16 patients: Complete response (CR) was observed in 8 patients (50%), one of them was with long-term CR (over 12 months after therapy); 5 have had relapse and 2 patients are still under treatment. Partial response (PR) was observed in 4 patients (25%), no response (NR) in 4 patients (25%). Side effects were moderate and self-limited. Loss of HCV-RNA was shown in some patients with PR and in all patients with CR, but only temporarily.     

Characterization of the effects of hepatitis C virus nonstructural 5A protein expression in human cell lines and on interferon-sensitive virus replication

The hepatitis C virus (HCV) nonstructural 5A (NS5A) protein has been implicated in the inherent resistance of HCV to interferon (IFN) antiviral therapy in clinical studies. Biochemical studies have demonstrated that NS5A interacts in vitro with and inhibits the IFN-induced, RNA-dependent protein kinase, PKR, and that NS5A interacts with at least one other cellular kinase. The present study describes the establishment and characterization of various stable NS5A-expressing human cell lines, and the development of a cell culture-based assay for determining the inherent IFN resistance of clinical NS5A isolates. Human epithelioid (Hela) and osteosarcoma (U2-OS) cell lines were generated that express NS5A under tight regulation by the tetracycline-dependent promoter. Maximal expression of NS5A occurred at 48 hours following the removal of tetracycline from the culture medium. The half-life of NS5A in these cell lines was between 4 to 6 hours. NS5A protein expression was localized cytoplasmically, with a staining pattern consistent with the location of the Golgi apparatus and endoplasmic reticulum. In the majority of cell lines, no obvious phenotypic changes were observed. However, three genotype 1b NS5A-expressing osteosarcoma cell lines exhibited cytopathic effect and severely reduced proliferation as a result of high-level NS5A expression. Full-length NS5A protein isolated from a genotype 1b IFN-nonresponsive patient (NS5A-1b) was capable of rescuing encephalomyocardititis virus replication during IFN challenge up to 40-fold, whereas a full-length NS5A-1a and an interferon sensitivity determining region (ISDR) deletion mutant (NS5A-1a-triangle upISDR) isolated from a genotype 1a IFN-nonresponsive patient showed no rescue activity. The NS5A-1b and NS5A-1a proteins also rescued vesicular stomatitis virus replication during IFN treatment by two- to threefold. These data cummulatively suggest that NS5A expression alone can render cells partially resistant to the effects of IFN against IFN-sensitive viruses, and that in some systems, these effects may be independent of the putative ISDR. A scenario is discussed in which the NS5A protein may employ multiple strategies contributing to IFN resistance during HCV infection.     

Mutations in the NS5A gene predict response to interferon therapy in Japanese patients with chronic hepatitis C and cirrhosis.

The virus genotype, serum HCV-RNA level and liver histology are reported to be important factors in the response to interferon therapy. Recent studies have revealed that HCV NS5A 2209-2248 amino acid changes affect the response to interferon therapy of genotype 1b chronic hepatitis C. In contrast, some studies done in western countries have reported no such correlation. In the present study, interferon therapy was given to 58 Japanese patients, including 15 liver cirrhosis patients. NS5A 2209-2248 changes, the serum HCV level, ALT level, age and histology were examined in relation to the interferon effect. Twenty-four of the 58 patients (41%) showed a sustained virological response to the therapy. The responses to interferon therapy were significantly correlated with NS5A 2209-2248 changes (p < 0.0001), the HCV-RNA level (p < 0.0001) and histology (p < 0.0060). Among 15 liver cirrhosis patients, 3 of 6 mutant type patients showed a sustained virological response; 5 intermediate and 4 with wild type virus infected patients showed no responses. In conclusion, NS5A 2209-2248 changes may be a useful predictive marker of response to interferon therapy in addition to the serum HCV RNA level even in histologically advanced patients.     

Introduction of NS5A mutations enables subgenomic HCV replicon derived from chimpanzee-infectious HC-J4 isolate to replicate efficiently in Huh-7 cells

Hepatitis C virus (HCV) subgenomic replicon has been reported to replicate efficiently and continuously in human hepatoma Huh-7 cells. To extend the previous results to other isolated HCV clones, we constructed another HCV replicon from HC-J4, one of chimpanzee-infectious HCV clones. An HCV replicon derived from HC-J4 (RpJ4) consists of HCV-5' untranslated region, neomycin phosphotransferase gene, the encephalomyocarditis virus internal ribosomal entry site, HCV nonstructural region, NS3 to NS5B, and HCV-3' untranslated region. The adaptive mutations known to be required for HCV-Con1 replicon were introduced in RpJ4 replicon, aa.(amino acids number according to HC-J4) 2197 serine to proline, deletion of serine at aa.2201, and aa.2204 serine to isoleucine (RpJ4-S2197P, RpJ4-S22001del, and RpJ4-S2204I). RpJ4/ISDR mutant and RpJ4-S2201del/ISDR mutant were also constructed by introducing six amino acid mutations into the interferon sensitivity determining region (ISDR). After transfection into Huh-7 cells and G418 selection, RpJ4 and RpJ4/ISDR mutants did not produce any colony. In contrast, G418-resistant cells were transduced efficiently by RpJ4-S2197P, RpJ4-S2204I, RpJ4-S2201del and RpJ4-S2201del/ISDR mutant, with the RpJ4-S2201del/ISDR mutant being most efficient. Hence the HCV replicon derived from HC-J4 can replicate efficiently following the introduction of adaptive mutations into the upstream region of ISDR. Moreover, additional introduction of mutations into ISDR further enhanced its replication. These findings demonstrate that the genetic structure of the NS5A domain is critical in HCV replications.     

Fluctuation patterns of HCV-RNA serum level in patients with chronic hepatitis C

The serum level of hepatitis C virus (HCV)-RNA is clinically important as a predictor of the response to interferon (IFN) therapy in patients with chronic hepatitis C. If serum HCV-RNA levels fluctuate during follow-up, and IFN therapy is begun at the time of a low HCV-RNA level, the IFN therapy may be more effective. We evaluated the fluctuation of HCV-RNA serum levels for 2 years in 212 patients with chronic hepatitis C, untreated with IFN who had HCV genotype 1b and an HCV-RNA level of 10 Meq/ml or more at first consultation. The HCV-RNA level was measured monthly for 2 years with an HCV branched DNA probe assay (b DNA probe assay). We classified HCV-RNA patterns into three types by the ratio of maximum HCV-RNA level (a) to minimum HCV-RNA level (b). In pattern 1 (constant type, 151 patients; 71.2%) the a/b ratio was 1–5. In pattern 2 (slight fluctuation type, 46 patients; 21.7%) the a/b ratio was 5–10. In pattern 3 (severe fluctuation type, 15 patients; 7.1%), the a/b ratio was 10 or more. Next, we evaluated the factors associated with the three patterns. Acute exacerbation of chronic hepatitis was regarded as an increase in serum alanine aminotransferase (ALT) level to more than 250 IU/l. The incidence of acute exacerbation for a 2-year follow-up was 13.9% (21/151) in pattern 1, 19.6% (9/46) in pattern 2, and 53.3% (8/15) in pattern 3. Multivariate analysis showed that acute exacerbation was the most important factor in the manifestation pattern 3. In conclusion, we found that: (1) about 70% of patients had a constant HCV-RNA levels for 2 years. (2) A few patients had severe fluctuation of serum HCV-RNA level after acute exacerbation of chronic hepatitis. Received: July 23, 1999 / Accepted: September 24, 1999     

Effect of treatment with interferon alpha-2b and ribavirin in patients infected with genotype 2 hepatitis C virus.

Aim: Nearly 20% of chronic hepatitis C (CHC) patients with genotype 2 hepatitis C virus (HCV) infection are not curable, even by interferon (IFN)-ribavirin combination therapy. The aim of this study is to investigate the factors that determine the efficacy of combination therapy in patients with genotype 2 HCV infection. Methods: Fifty patients with CHC who underwent a treatment of 6 MU IFN alpha-2b with ribavirin for 24 weeks were retrospectively analyzed. Results: All the patients showed no serum HCV-RNA within 12 weeks after starting the therapy. Forty-one of the 50 patients (82%) achieved a sustained virological response (SVR). The age, sex, genotype (2a vs. 2b) and grade/stage of the liver by histopathology and pretreatment viral load werenot different between the sustained responders and relapsers. Univariate analysis showed that an earlier viral clearance from blood and a larger number of amino acid substitutions in the interferon sensitivity determining region (ISDR) were predictors of SVR. Multivariate analysis showed that a large number of amino acid substitutions in the ISDR was a predictor of SVR. Conclusion: The characterization of the amino acid sequences of ISDR may be helpful for predicting a relapse after combination therapy in patients with genotype 2 HCV infection.     

Hepatitis C virus clearance is prominent in women in an endemic area

BACKGROUND: The clinical and virological backgrounds of cases with previous hepatitis C virus (HCV) infection (positive for HCV antibody (anti-HCV) and HCV-RNA negative) in an HCV endemic area were examined to identify factors related to the clearance of HCV. METHODS: The study population comprised 3117 inhabitants, 1037 male and 2080 female, from an HCV endemic area. Hepatitis C virus antibody was detected by a passive haemagglutination test. The HCV-RNA and the HCV genotype were detected by using the polymerase chain reaction method. The HCV serotype was determined by enzyme immunoassay by using the peptides of the core region. RESULTS: Twenty-two per cent of the inhabitants were positive for anti-HCV, with males and the elderly having a significantly higher antibody titre (P < 0.01) than youths and females. Hepatitis C virus-RNA was detected in 78% of the HCV antibody-positive cases. The rate of HCV-RNA positivity was significantly higher in males than in females (P < 0.01). No relationship was found between HCV-RNA positivity and age. The HCV genotype 1b was the predominant genotype among the HCV-RNA-positive cases. Mixed genotypes (1b + 2a) were observed in 12% of cases, primarily in elderly males and females. In cases with previous HCV infection, serotype 1 was the most common serotype, and there appeared to be no relationship between the distribution of HCV serotypes and age and gender. There was a female predominance with regard to previous HCV infection, but not to being HCV carriers (P < 0.01). CONCLUSIONS: Gender, not HCV genotype, is the primary factor influencing HCV clearance.     

Efficacy and changes of the nonstructural 5A GENE by prolonged interferon therapy for patients with hepatitis C virus genotype 1b and a high level of serum HCV-RNA.

OBJECT: The aim of this study was to examine the efficacy and the changes of amino acid sequences of the interferon sensitivity-determining region (ISDR) by prolonged interferon (IFN) treatment in patients who have serum hepatitis C virus (HCV)-genotype 1b and a high level of serum HCV-RNA. METHODS: Inclusion criteria were biopsy-proven chronic hepatitis, positive HCV-RNA, and an abnormal serum aminotransferase level. Twenty-five patients received 6 MU of natural IFN-alpha daily for 8 weeks, followed by three times weekly for 40 weeks (1,056 MU). One patient was withdrawn from the study due to IFN side effects. Therefore, the remaining 24 patients (group 1) were studied the efficacy of IFN administration and changes of ISDR. As a control, 22 patients (group 2) treated with natural IFN-alpha for 24 weeks for the same period were studied retrospectively. Patients were defined as complete responders (CR) if serum HCV-RNA levels were negative for 6 months after IFN therapy. RESULTS: According to this criterion, CR was 25% (6/24) in group 1 and 9.1% (2/22) in group 2. The normalization rates of alanine aminotransferease (ALT) for six months after termination of IFN was 41% (10/24) in group 1 and 18.2% (4/22) in group 2. Regarding the changes of ISDR in patients with no CR, the change rates of ISDR were 16.7% (3/18) in group 1 and 10% (2/20) in group 2. CONCLUSION: We concluded that prolonged IFN therapy was effective for patients with HCV-genotype 1b and a high level of serum HCV-RNA.     

NS5A mutations predict biochemical but not virological response to interferon-α treatment of sporadic hepatitis C virus infection in European patients

The NS5A region of the hepatitis C virus (HCV) genome has been reported by Japanese but not European investigators to be a significant factor in predicting interferon (IFN) response patients with HCV of genotype 1. We correlated the NS5A region with treatment outcome in patients with sporadic HCV infection. Twenty‐eight patients (10 men, 18 women, mean age 60 ± 2 years) with histologically proven HCV chronic hepatitis, genotype 1b, were treated with 6 MU IFN‐α for 6 months. The 6954–7073 area of the NS5A region was directly sequenced for nucleotide and amino acids mutations and the results were related to biochemical and virological response. None of the patients had a strain with nucleotide sequence identical to the Japanese HCV‐J. However, in five strains the nucleotide mutations led to synonymous amino acids and the amino acid sequences were identical to the prototype Japanese strain. Only 2/28 patients had four or more amino acid mutations (mutant strains) while 21 demonstrated an intermediate type and five belonged to the wild‐type. The most frequent non‐synonymous substitution was at position 6982 (A→G) corresponding to an amino acid change at codon 2218 (His→Arg). All patients with the wild‐type were biochemical nonresponders while the two patients with the mutant strains had a sustained biochemical response. Twenty‐three percent of the intermediate type had a sustained biochemical response. NS5A mutations predict the biochemical but not the virological response of patients. Virological response was poor and unrelated to the type of HCV strain. Biochemical responders had significantly lower amino acid mutations (1.14 ± 0.19) compared with nonresponders (2.57 ± 1.4, P < 0.003) as well as lower aminotransferase values (P < 0.01). Hence, mutational analysis of the NS5A region showed that our patients have a mutational profile similar to the European studies with a wild‐type that is slightly different from the Japanese HCV‐J sequence. The biochemical, but not the virological response to IFN‐α is similar to the Japanese studies, with no response of the patients with wild‐type sequence, a good response in the limited number of patients with mutant strains and 23% response rate in the patients with intermediate type sequences.     

Short-term prolongation of pegylated interferon and ribavirin therapy for genotype 1b chronic hepatitis C patients with early viral response

Aim:  We tailored extended treatments using pegylated interferon (PEG IFN) and ribavirin (RBV) to viral responses after initiation of therapy and investigated the efficacy and safety of its therapy for chronic hepatitis C (CHC) patients.
Methods:  Eighty-two genotype 1b CHC patients were enrolled in the present study. All patients received PEG IFN-α-2b and weight-based RBV therapy. We defined a viral response in which serum HCV-RNA is undetectable at week 4 as rapid viral response (RVR), detectable at week 4 and undetectable by week 12 as early viral response (EVR), and detectable at week 12 and undetectable by week 24 as late viral response (LVR). We set the treatment duration depending on viral response; 48 weeks for RVR patients and 72 weeks for LVR. Furthermore, EVR patients received a short-term extension of treatment duration to 52–60 weeks. We prospectively investigated sustained viral response (SVR) rates of these groups.
Results:  Overall SVR rate for the total patient group was 57.3%. SVR rates of the RVR, EVR and LVR patients were 100%, 80.5% and 40.0%, respectively. Nine patients could not complete this treatment protocol. Baseline platelet count and mutation in the interferon sensitivity-determining region of NS5A were significant independent predictors of SVR, and amino acid substitution of the core region was a significant independent predictor of non-viral response by multivariate logistic regression analyses.
Conclusion:  The results indicate that short-treatment extension of PEG IFN plus RBV treatment protocols in EVR patients can improve overall SVR rates.     

Effect of treatment with interferon α-2b and ribavirin in patients infected with genotype 2 hepatitis C virus

Aim:  Nearly 20% of chronic hepatitis C (CHC) patients with genotype 2 hepatitis C virus (HCV) infection are not curable, even by interferon (IFN)–ribavirin combination therapy. The aim of this study is to investigate the factors that determine the efficacy of combination therapy in patients with genotype 2 HCV infection.
Methods:  Fifty patients with CHC who underwent a treatment of 6 MU IFN α-2b with ribavirin for 24 weeks were retrospectively analyzed.
Results:  All the patients showed no serum HCV-RNA within 12 weeks after starting the therapy. Forty-one of the 50 patients (82%) achieved a sustained virological response (SVR). The age, sex, genotype (2a vs. 2b) and grade/stage of the liver by histopathology and pretreatment viral load werenot different between the sustained responders and relapsers. Univariate analysis showed that an earlier viral clearance from blood and a larger number of amino acid substitutions in the interferon sensitivity determining region (ISDR) were predictors of SVR. Multivariate analysis showed that a large number of amino acid substitutions in the ISDR was a predictor of SVR.
Conclusion:  The characterization of the amino acid sequences of ISDR may be helpful for predicting a relapse after combination therapy in patients with genotype 2 HCV infection.     

Role of serum soluble Fas/soluble Fas ligand and TNF-alpha on response to interferon-alpha therapy in chronic hepatitis C

AIMS/BACKGROUND: To determine the relationship between host factors and host response to interferon (IFN) therapy, serum soluble Fas (sFas), soluble Fas ligand (sFas ligand), and tumor necrosis factor-alpha (TNF-alpha) were analyzed in 41 patients with chronic hepatitis C (CH-C) treated with IFN-alpha. METHODS: Serum levels of sFas, sFas ligand, and TNF-alpha were measured at 0, 4, and 24 weeks of IFN therapy. RESULTS: Eighteen patients were complete responders (CR) and 23 patients were non-responders (NR). Serum levels of sFas and TNF-alpha in patients with CHC were significantly higher than those in healthy controls (p<0.01 and p<0.01, respectively). Serum sFas ligand levels were significantly lower in CH-C patients than in healthy controls (p<0.01). Before IFN therapy, serum levels of sFas in NR were significantly higher than those in CR (p<0.05). At 4 weeks of IFN therapy, serum levels of sFas of CR were significantly elevated compared with levels before IFN therapy (p<0.05). Serum levels of sFas correlated with the histological activity of the liver (p<0.05) and alanine aminotransferase (p<0.05). None of the three parameters, serum sFas, sFas ligand, or TNF-alpha levels, correlated with each other, with HCV-RNA genotype or with serum HCV-RNA load. Multiple logistic regression analysis showed that serum sFas levels before IFN therapy were a contributive factor to predict efficacy of IFN therapy. CONCLUSIONS: Serum sFas/sFas ligand and TNF-alpha play a possible role in pathogenesis of CH-C and also in IFN therapy. Serum sFas levels before IFN therapy may be one of the host-related factors used for evaluating the response of CH-C patients to IFN therapy.