Typing hepatitis C virus by polymerase chain reaction with type-specific primers: application to clinical surveys and tracing infectious sources

Sequence heterogeneity in NS5A of hepatitis C virus genotypes 2a and 2b and clinical outcome of pegylated-interferon/ribavirin therapy

Pegylated-interferon plus ribavirin (PEG-IFN/RBV) therapy is a current standard treatment for chronic hepatitis C. We previously reported that the viral sequence heterogeneity of part of NS5A, referred to as the IFN/RBV resistance-determining region (IRRDR), and a mutation at position 70 of the core protein of hepatitis C virus genotype 1b (HCV-1b) are significantly correlated with the outcome of PEG-IFN/RBV treatment. Here, we aimed to investigate the impact of viral genetic variations within the NS5A and core regions of other genotypes, HCV-2a and HCV-2b, on PEG-IFN/RBV treatment outcome. Pretreatment sequences of NS5A and core regions were analyzed in 112 patients infected with HCV-2a or HCV-2b, who were treated with PEG-IFN/RBV for 24 weeks and followed up for another 24 weeks. The results demonstrated that HCV-2a isolates with 4 or more mutations in IRRDR (IRRDR[2a]≥4) was significantly associated with rapid virological response at week 4 (RVR) and sustained virological response (SVR). Also, another region of NS5A that corresponds to part of the IFN sensitivity-determining region (ISDR) plus its carboxy-flanking region, which we referred to as ISDR/+C[2a], was significantly associated with SVR in patients infected with HCV-2a. Multivariate analysis revealed that IRRDR[2a]≥4 was the only independent predictive factor for SVR. As for HCV-2b infection, an N-terminal half of IRRDR having two or more mutations (IRRDR[2b]/N≥2) was significantly associated with RVR, but not with SVR. No significant correlation was observed between core protein polymorphism and PEG-IFN/RBV treatment outcome in HCV-2a or HCV-2b infection. Conclusion: The present results suggest that sequence heterogeneity of NS5A of HCV-2a (IRRDR[2a]≥4 and ISDR/+C[2a]), and that of HCV-2b (IRRDR[2b]/N≥2) to a lesser extent, is involved in determining the viral sensitivity to PEG-IFN/RBV therapy.

Detection of hepatitis C virus subtypes 6a, 6n, 6w and mixed infections using a modified multiplex real-time polymerase chain reaction protocol

BACKGROUND/PURPOSE

In the past few years, many new subtypes in hepatitis C virus (HCV) genotype 6 have been identified. The aim of this study was to modify the multiplex real-time polymerase chain reaction (RT-PCR) protocol and use it to determine the HCV subtypes of a group of Taiwanese injection drug users (IDUs).

METHODS

We used 76 serum specimens collected in northern Taiwan in 2008. Multiplex RT-PCR was used for HCV subtyping among those serum samples having anti-HCV antibodies. Twenty cases were randomly selected for comparison with subtyping results from Inno-LiPa II tests and phylogenetic tree analysis using NS5B sequences.

RESULTS

Multiplex RT-PCR assays showed that 60.5% (46/76) of IDUs had single HCV infection. Three out of 76 (3.9%) had double HCV infection (1b/6a, 2a/2b and 2b/6a). Besides this, 27.6% (21/76) had no HCV signal. One IDU had subtype 6n and two had subtype 6w infection. Inno-LiPa II tests misclassified all 6n and 6w cases as 1b subtype.

CONCLUSION

Our modified multiplex RT-PCR protocol can be used to support molecular epidemiological studies and laboratory diagnoses of different HCV subtypes including genotype 6.

Response to peginterferon-alfa 2b and ribavirin in Japanese patients with chronic hepatitis C genotype 2

BACKGROUND

The current standard treatment for patients infected with hepatitis C virus (HCV) of genotype 2 is the combination of peginterferon (PEG-IFN) plus ribavirin (RBV) for 24 weeks.

AIMS

We assessed the sustained virological response (SVR) rates in HCV genotype 2-infected Japanese patients in relation to the duration of treatment.

METHODS

Between 2006 and 2009, among 147 patients with HCV genotype 2-infection in Chiba Prefecture, 138 consecutive patients were finally enrolled. Twenty-one, 97 and 20 patients were treated with PEG-IFN-alfa 2b plus RBV for 16, 24 and 48 weeks, respectively. Epidemiological data and treatment outcomes were retrospectively evaluated. HCV RNA was measured with COBAS AMPLICOR HCV Monitor Test v. 2.0.

RESULTS

The overall SVR rate was 82.6% (114 of 138): treatment-naïve patients, 86.4% (89 of 103); patients with history of previous treatment, 71.4% (25 of 35). Patients treated for 16, 24 and 48 weeks obtained SVR rates of 66.6% (14 of 21), 86.5% (84 of 97) and 80.0 (16 of 20), respectively.

CONCLUSIONS

The SVR rates of PEG-IFN-alfa 2b plus RBV in Japanese patients were similar to those in previous studies. Combination treatment for 24 weeks for some patients infected with HCV genotype 2 may be superior to that for 16 weeks. More precise patient selection will be needed to shorten the combination treatment.

Sequence heterogeneity of NS5A and core proteins of hepatitis C virus and virological responses to pegylated-interferon/ribavirin combination therapy

Both host and viral factors have been implicated in influencing the response to pegylated-interferon/ribavirin (PEG-IFN/RBV) therapy for hepatitis C virus (HCV) infection. Among the viral factors, sequence heterogeneity within NS5A and core regions has been proposed. This study aimed to clarify the relationship between virological responses to PEG-IFN/RBV therapy and sequence heterogeneity within NS5A, including the IFN/RBV resistance-determining region (IRRDR), the interferon sensitivity-determining region (ISDR) and the core region. Pretreatment sequences of NS5A and the core regions were analyzed in 57 HCV-1b-infected patients who were to be treated with PEG-IFN/RBV. Of 40 patients infected with HCV having an IRRDR with four or more mutations (IRRDR ≥ 4), 28 (70%) patients achieved a sustained virological response (SVR). On the other hand, only 4 (24%) of 17 patients infected with HCV having an IRRDR with three or fewer mutations (IRRDR ≤ 3) achieved a SVR (P = 0.001). Similarly, 22 (71%) of 31 patients infected with HCV and having an ISDR with one or more mutations (ISDR ≥ 1) achieved a SVR while 10 (38%) of 26 patients infected with HCV and having an ISDR without any mutations (ISDR = 0) achieved a SVR (P = 0.014). As for the core region, there was significant correlation between a single mutation at position 70 (Gln(70) ) and non-SVR (P = 0.02). Notably, Gln(70) was more prominently associated with the null response (P = 0.0007). In conclusion, sequence heterogeneity within the IRRDR and ISDR, and a single point mutation at position 70 of the core region of HCV-1b are likely to be correlated with virological responses to PEG-IFN/RBV therapy.

Molecular epidemiology of a hepatitis C virus outbreak in a leprosy sanatorium in Japan

The hepatitis C virus (HCV) outbreak that occurred between 1940 and 1999 in a closed leprosy sanatorium located on a small island in Japan was analyzed. The analysis of 318 nucleotides in the NS5B region of HCV allowed us to establish the existence of at least three different HCV strains in this sanatorium.

Elevation of plasma soluble human leukocyte antigen-G in patients with chronic hepatitis C virus infection

The subversion of immune responses that hepatitis C virus (HCV) uses to escape immune surveillance and to establish persistent infection has been poorly understood. The immune-suppressive molecule human leukocyte antigen-G (HLA-G) has been supposed to play important roles in viral infection. In the current study, HCV genotype was analyzed in 67 chronic HCV-infected (CHC) patients. Plasma soluble sHLA-G (including sHLA-G1 and HLA-G5), interleukin-10 (IL-10), and interferon-γ (IFN-γ) levels were determined in these CHC patients and in healthy subjects by enzyme-linked immunosorbent assay, and the sHLA-G isoforms present in plasma were determined by Western blot. Data showed that HCV 1b was the predominant genotype, with a prevalence of 64.2%. sHLA-G was dramatically increased in CHC patients (median: 85.54 U/ml, range: 19.40-204.07) over that in normal controls (median: 9.13 U/ml, range: 5.07-69.56) (p < 0.001). Western blotting revealed that plasma sHLA-G was derived from sHLA-G1 and HLA-G5. IL-10 and IFN-γ levels were also significant higher in CHC patients than in normal controls (median: 16.3 pg/ml vs 1.8 pg/ml, p < 0.001, and 1025.3 pg/ml vs 858.3 pg/ml, p = 0.03, respectively). No significant association was observed for the HCV genotype and viral RNA load with the levels of sHLA-G, IL-10, and IFN-γ in CHC patients. These results indicate that elevation of sHLA-G expression in HCV patients was independent of viral genotype and viral RNA load. Given its immunotolerant property, an increase in sHLA-G may play a role in the persistency of HCV infection.

Polymorphisms of hepatitis C virus non-structural protein 5A and core protein and clinical outcome of pegylated-interferon/ribavirin combination therapy

OBJECTIVE

Hepatitis C virus (HCV genome) polymorphisms are thought to influence the outcome of pegylated-interferon/ribavirin (PEG-IFN/RBV) therapy. This study aimed to examine non-structural protein 5A (NS5A) polymorphisms, e.g. IFN/RBV resistance-determining region (IRRDR) and IFN sensitivity-determining region (ISDR), and core protein polymorphism as predictive therapeutic markers.

METHODS

Pretreatment sequences of NS5A and core regions were analyzed in 68 HCV-1b-infected patients treated with PEG-IFN/RBV.

RESULTS

Of 24 patients infected withHCV having an IRRDR with 6 or more mutations (IRRDR≥6), 18 (75%) patients achieved sustained virological response (SVR), whereas only 11 (25%) of 44 patients infected with HCV having IRRDR≤5 did. IRRDR≥6 was significantly associated with SVR (p < 0.0001). On the other hand, ISDR≥2 was significantly associated with relapse (either before [breakthrough] or after end-of-treatment response [ETR[-]relapse]) (p < 0.05) and a point mutation of the core protein from Arg to Gln at position 70 (Gln(70)) was significantly associated with null-response (p < 0.05). Multivariate analysis identified IRRDR≥6 as the only viral genetic factor that independently predicted SVR.

CONCLUSION

NS5A (IRRDR and ISDR) and core protein polymorphisms are associated with the outcome of PEG-IFN/RBV therapy for chronic hepatitis C. In particular, IRRDR≥6 is a useful marker for prediction of SVR.

Detection of hepatitis C virus and antibodies in postmortem blood and bloodstains

To evaluate the risk of accidental hepatitis C virus (HCV) infection, we examined whether anti-HCV antibodies and HCV RNA were detectable in HCV-infected blood samples from living donors, cadavers, and bloodstains. We showed that even after blood has left the body for several days, anti-HCV antibodies and HCV RNA may persist in it.

Efficacy and cost-effectiveness of consensus interferon monotherapy with high-dose induction for hepatitis C patients with genotype 2

OBJECTIVE

Several treatment strategies for patients with chronic hepatitis C have been compared mainly in terms of their efficacy, and it has been found that pegylated interferon (IFN) plus ribavirin has become the standard therapy, but aged patients may not tolerate ribavirin and the cost-effectiveness of treatment should also be further considered. We conducted a study to evaluate the efficacy, safety, and cost-effectiveness of consensus IFN monotherapy with high-dose induction for patients with chronic hepatitis C in clinical practice.

MATERIAL AND METHODS

We consecutively enrolled 104 patients with chronic hepatitis C. Patients were scheduled to receive 12 or 18 μg of consensus IFN daily for 2 weeks, then three times a week for 22 weeks. Efficacy, safety, and cost-effectiveness were assessed. A Markov model was developed to investigate cost-effectiveness in patients with chronic hepatitis C treated by different IFN-based treatment strategies.

RESULTS

Of the 104 study patients, a sustained virological response (SVR) was achieved in 66 (63%). Logistic regression analysis revealed that genotype 2, lower hepatitis C virus RNA levels, and patient age were independently associated with SVR. The response rate was significantly higher in patients with genotype 2 (51/66, 77%) versus genotype 1 (15/38, 40%). Cost-effectiveness analysis in patients with genotype 2 revealed that high-dose induction with consensus IFN monotherapy was as highly cost-effective as pegylated IFN plus ribavirin.

CONCLUSION

Consensus IFN monotherapy with high-dose induction shows high efficacy and cost-effectiveness in chronic hepatitis C patients with genotype 2 infection. Thus, it may be a reliable alternative in aged patients and for those excluded from standard combination therapy.

Hepatitis C virus: How genetic variability affects pathobiology of disease

As an RNA virus, hepatitis C virus (HCV) shows a characteristically high level of nucleotide diversity. Accumulation of nucleotide substitutions in the virus has resulted in diversification into quasispecies, subtypes and distinct genotypes. Pathobiological studies linking nucleotide and amino acid sequences with clinical findings have identified relationships between certain genotypes and characteristic biological properties. Genotype 3 HCV infection was found to be associated with a high level of liver steatosis. Genotypes 1 and 4 were found to be more resistant to interferon (IFN) based therapies than genotypes 2 and 3. Studies of genotype 1 sequences obtained from patients treated with IFN have identified a relationship between favorable response to interferon therapy and amino acid substitutions in the NS5A region (interferon response determining region; ISDR). Further studies have identified a relationship between the effect of IFN therapy and other regions of the NS5A protein. More recently, a relationship has been found between poor response to peg-IFN plus ribavirin combination therapy and substitutions at amino acid 70 and 91 in the core protein. Furthermore, a correlation between human genetic variation in the IL28B (IFN-lamda 3) locus and core amino acid substitutions has been characterized. In this review we briefly summarize the discovery, classification and nomenclature of HCV genotypes and subtypes. We also discuss amino acid substitutions within specific regions that have been reported to be associated with outcome of IFN and peg-IFN plus ribavirin combination therapy.

A shift in the hepatitis C virus genotype dominance in blood donor samples from Thailand

Hepatitis C virus (HCV) can be classified into six major genotypes. The HCV genotypes variability accounts for its geographical distribution, its responses to treatments and the clinical outcomes. The aim of this study was to determine the distribution of HCV genotypes among volunteer blood donors in Thailand. Samples from 135 anti-HCV positive blood donors were analyzed. HCV RNA and genotyping was carried out using nested polymerase chain reaction (PCR) and genotype-specific primer PCR for a portion of the core region. HCV RNA was detected in 109 samples (80.7%). Genotype analysis demonstrated four different genotypes. The most common was genotype 3a (36.7%), followed by genotype 6 (29.4%), 1a (19.3%), 1b (6.4%) and mixed infection (1.8%). Seven samples were untyped (6.4%) in the present study. In several previous reports, the prevalence found in Thailand was HCV genotypes 3, 1 and 6. The present results show an increasing importance of the genotype 6 in HCV infections. This study has also described for the first time in Thailand mixed infections of HCV genotypes.

Peginterferon-alpha-2b plus ribavirin therapy in patients with chronic hepatitis C as assessed by a multi-institutional questionnaire in Japan

BACKGROUND AND AIM

There has so far been no questionnaire report on patients who were treated with peginterferon plus ribavirin (PEG IFN+RBV) therapy. The purpose of this study was to investigate the problems of this therapy by a questionnaire survey.

PATIENTS AND METHODS

A survey of 681 patients with chronic hepatitis C who received treatment with PEG IFN+RBV was conducted in the Kyushu region of Japan. Using an original questionnaire, the survey was conducted prior to the treatment, during the third month of treatment, at the completion of treatment or the discontinuation of treatment, and at 6 months after the completion of treatment.

RESULTS

It was indicated that the patients had a high level of comprehension and understanding of chronic hepatitis C and PEG IFN+RBV treatment. However, the results also indicated that patients had a high level of anxiety. Side effects were adequately dealt with by physicians. However, dermatological symptoms were not adequately explained to the patients, although they were the second most severe side-effect. It was also revealed that side-effects were most distressing during the first and second months after the start of treatment.

CONCLUSION

The questionnaire survey provided new information that has never been reported. It is believed that understanding this information is important for future treatment.

Hepatitis C virus infection in a Japanese leprosy sanatorium for the past 67 years

Oku-Komyo-En is one of the national leprosy sanatoria, located on a small island in Setouchi city, Okayama prefecture of Japan since 1938. Since autopsies were carried out routinely on almost all patients who had died in the sanatorium up to 1980, approximately 1,000 formalin-fixed autopsy tissue samples were available for analysis. When these samples were reviewed, the pathological data indicated a sharp rise in the death rate caused by cirrhosis of the liver and hepatocellular carcinoma (HCC) since 1960 and 1970, respectively. Hepatitis C virus (HCV) infection is a common cause of HCC in Japan. The presence of HCV RNA was demonstrated in paraffin sections prepared from the autopsied liver tissue fixed in formalin for a prolonged period of time, by employing nested RT-PCR using type-specific primers. The data showed that HCV RNA was detectable in samples of the liver archived as early as 1940, representing the liver tissues kept in formalin for up to 67 years. HCV genotypes 1b and 2a were found by RT-PCR at 85.7% and 14.3%, respectively, in patients with leprosy.

Distribution of different hepatitis C virus genotypes in patients with hepatitis C virus infection

AIM

To investigate the presence of mixed infection and discrepancy between hepatitis C virus (HCV) genotypes in plasma, peripheral blood mononuclear cells (PBMCs), and liver biopsy specimens.

METHODS

From September 2008 up to April 2009, 133 patients with chronic hepatitis C referred to Firouzgar Hospital for initiation of an antiviral therapy were recruited in the study. Five milliliters of peripheral blood was collected from each patient and liver biopsy was performed in those who gave consent or had indications. HCV genotyping was done using INNO-LiPA(TM) HCV II in serum, PBMCs, and liver biopsy specimens and then confirmed by sequencing of 5'-UTR fragments.

RESULTS

The mean age of patients was 30.3 +/- 17.1 years. Multiple transfusion was seen in 124 (93.2%) of patients. Multiple HCV genotypes were found in 3 (2.3%) of 133 plasma samples, 9 (6.8%) of 133 PBMC samples, and 8 (18.2%) of 44 liver biopsy specimens. It is notable that the different genotypes found in PBMCs were not the same as those found in plasma and liver biopsy specimens.

CONCLUSION

Our study shows that a significant proportion of patients with chronic hepatitis C are affected by multiple HCV genotypes which may not be detectable only in serum of patients.

Zinc supplementation improves the outcome of chronic hepatitis C and liver cirrhosis

We treated patients with C-viral chronic hepatitis (CH) and liver cirrhosis (LC) with polaprezinc and determined prospectively the effect on long-term outcome. 62 patients were enrolled. Of these, 32 were administered 1.0 g polaprezinc and the remainder were not administered polaprezinc. We measured the serum zinc concentrations using conventional atomic absorption spectrometry and conducted a prospective study to determine the long-term outcome of the polaprezinc therapy. Changes of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the polaprezinc administration group were significantly lower than those of the untreated group. The decrease in platelet count was clearly less than that of the untreated group. The factors that inhibited increases in serum zinc concentrations following administration of polaprezinc included low serum zinc concentration states. Furthermore, the reductions of AST and ALT levels in the low zinc group were significantly greater than those of the high zinc group. When the patients who were administered polaprezinc were divided into two groups whose zinc concentrations increased (zinc responders) or remained stable or decreased (zinc non-responders), the zinc responders had a clearly lower cumulative incidence of HCC than the zinc non-responders. We conclude zinc supplementation improved the long-term outcome in C-viral CH and LC patients.

Zinc supplementation improves the outcome of chronic hepatitis C and liver cirrhosis

We treated patients with C-viral chronic hepatitis (CH) and liver cirrhosis (LC) with polaprezinc and determined prospectively the effect on long-term outcome. 62 patients were enrolled. Of these, 32 were administered 1.0 g polaprezinc and the remainder were not administered polaprezinc. We measured the serum zinc concentrations using conventional atomic absorption spectrometry and conducted a prospective study to determine the long-term outcome of the polaprezinc therapy. Changes of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the polaprezinc administration group were significantly lower than those of the untreated group. The decrease in platelet count was clearly less than that of the untreated group. The factors that inhibited increases in serum zinc concentrations following administration of polaprezinc included low serum zinc concentration states. Furthermore, the reductions of AST and ALT levels in the low zinc group were significantly greater than those of the high zinc group. When the patients who were administered polaprezinc were divided into two groups whose zinc concentrations increased (zinc responders) or remained stable or decreased (zinc non-responders), the zinc responders had a clearly lower cumulative incidence of HCC than the zinc non-responders. We conclude zinc supplementation improved the long-term outcome in C-viral CH and LC patients.

Clinical evaluation of a colorimetric oligonucleotide chip for genotyping hepatitis C virus

INTRODUCTION

Hepatitis C virus (HCV) is a major cause of chronic liver disease worldwide. It is associated with the development of end-stage liver disease and hepatocellular carcinoma. Studies have shown that determination of hepatitis C virus (HCV) genotypes is clinically important for prediction of the clinical course and the outcome of antiviral therapy. The aim of this study was to evaluate a colorimetric oligonucleotide chip, which can be used for the rapid and economical detection of the genotypes/subtypes of hepatitis C virus.

DESIGN AND METHODS

A total of 860 serum specimens were tested by an oligonucleotide chip genotyping test. Partial genotype results were compared with those obtained by sequencing method and INNOLiPA HCV II assay. The relative sensitivities of the methods were assessed by using the 5'NCR amplicon from the HCV RNA fluorescent amplicor HCV tests and Light Cycler.

RESULTS

Of 860 serum specimens tested for their genotypes/subtypes by the oligonucleotide array, 607 HCV positive serum samples could be typed by the sequencing method and 60 of 607 HCV positive serum specimens were typed by INNOLiPA HCV II method. Identification of genotype/subtypes by nucleotide sequencing and INNOLiPA HCV II assay showed respective coincidence rates of 99.8% and 96.7% with the HCV oligonucleotide chip results. And the colorimetric method exhibited 99.8% of relative sensitivity compared with the fluorescent amplicor HCV tests.

CONCLUSION

To our knowledge this oligonucleotide chip genotyping method offers a fast and convenient way to determine the genotype in large-scale settings. The tests can be easily adapted by a clinical diagnostic laboratory.

Cellular immune response to infection by different genotypes of hepatitis C virus

The present study aimed to estimate the cellular immune response to infection by different HCV genotypes in some Egyptian patients with chronic liver disease. HCV-RNA and HCV genotypes were conducted using type-specific primers to amplify the core region of HCV genome. The levels of IFN-gamma and TNF-alpha, PIIINP, SOD enzyme were also determined. The results showed that genotype 4 was the prevalent one (88.57%).Genotype 3 was found mixed with genotype 2 and 4 (11.42% and 34.28% respectively). Genotype 1 was absent from patients under study. No significant differences were observed in the level of IFN-gamma interferon, SOD enzyme and ALT enzyme between those genotypes. On the other hand the level of TNF-alpha was greatly increased in patients infected with mixed HCV genotypes 3, 4 compared with patients with genotype 4 and those infected with mixed genotypes 2, 3. Otherwise PIIINP was decreased significantly of the same group compared with other groups.

A randomized trial of 24 versus 48 weeks of peginterferon α-2a in patients infected with chronic hepatitis C virus genotype 2 or low viral load genotype 1: a multicenter national study in Japan

In a country such as Japan with the average age of patients with chronic hepatitis C treated with antivirals sometimes well above 60 years, the standard combination therapy is not well tolerated. In this randomized, prospective, controlled trial, we investigated the efficacy of 24-week peginterferon α monotherapy for easy-to-treat patients. A total of 132 patients chronically infected with hepatitis C virus (HCV) genotype 2 (n = 115) or low viral load HCV genotype 1 (<100 kIU/ml, n = 17) were treated with peginterferon α-2a (180 μg/week). Patients with a rapid virological response (RVR, HCV RNA negative or <500 IU/ml at week 4) were randomized for a total treatment duration of 24 (group A) or 48 (group B) weeks. Patients who did not show RVR (group C) were treated for 48 weeks. Sustained virological response (SVR) was assessed by qualitative reverse-transcription polymerase chain reaction. One hundred eight of 132 (82%) patients with RVR were randomized. SVR rates were 60% (group A), 79% (group B), and 27% (group C), respectively. Similar SVR rates were achieved in patients infected with HCV genotype 2 with low pretreatment viral load (<1000 kIU/ml) in group A (81%) and group B (79%) (P = 0.801), whereas in those with higher viral load (≥1000 kIU/ml), a lower SVR rate was identified in group A (26%) than in group B (67%) (P = 0.041). In conclusion, in patients infected with HCV genotype 2 and pretreatment viral load below 1000 kIU/ml who achieve RVR, 24-week treatment with peginterferon α-2a alone is clinically sufficient. Those who show no RVR or have higher baseline viral load, require alternative therapies.

Clinical trial: extended treatment duration of peginterferon-alpha2b plus ribavirin for 72 and 96 weeks in hepatitis C genotype 1-infected late responders

BACKGROUND

The benefits of prolonging peginterferon and ribavirin after 48 weeks of treatment to maximize sustained virological responses (SVR) in hepatitis C virus (HCV) genotype 1-infected patients remain to be understood.

AIM

To investigate whether extended treatment longer than 72 weeks may be superior to 72-week treatment.

METHODS

A total of 120 treatment-naïve or retreated patients with HCV genotype 1 were treated with peginterferon-alpha-2b (1.5 microg/kg/week) plus weight-based ribavirin. We had 34 late responders, in whom HCV RNA first became undetectable at week 12-48, and randomized them into three groups receiving standard-dose peginterferon-alpha-2b plus low-dose ribavirin (200 mg/day) for extended 24 weeks (group A), receiving low-dose peginterferon-alpha-2b (0.75 microg/kg/week) plus low-dose ribavirin for extended 48 weeks (group B) or no extended treatment (group C), and evaluated the outcome according to their virological response.

RESULTS

Multivariate analysis showed that the treatment for 96 weeks was identified as a significant, independent factor associated with SVR in HCV genotype 1-infected late responders in comparison with group A [odds ratio (OR), 10.002; P = 0.080] and group C (OR, 17.748; P = 0.025).

CONCLUSION

Extending the treatment duration from 48 weeks to 96 weeks improves SVR rates in genotype 1-infected patients with late virological response to peginterferon-alpha-2b and ribavirin.

HCV genotyping using statistical classification approach

The genotype of Hepatitis C Virus (HCV) strains is an important determinant of the severity and aggressiveness of liver infection as well as patient response to antiviral therapy. Fast and accurate determination of viral genotype could provide direction in the clinical management of patients with chronic HCV infections. Using publicly available HCV nucleotide sequences, we built a global Position Weight Matrix (PWM) for the HCV genome. Based on the PWM, a set of genotype specific nucleotide sequence "signatures" were selected from the 5' NCR, CORE, E1, and NS5B regions of the HCV genome. We evaluated the predictive power of these signatures for predicting the most common HCV genotypes and subtypes. We observed that nucleotide sequence signatures selected from NS5B and E1 regions generally demonstrated stronger discriminant power in differentiating major HCV genotypes and subtypes than that from 5' NCR and CORE regions. Two discriminant methods were used to build predictive models. Through 10 fold cross validation, over 99% prediction accuracy was achieved using both support vector machine (SVM) and random forest based classification methods in a dataset of 1134 sequences for NS5B and 947 sequences for E1. Prediction accuracy for each genotype is also reported.

HCV antibody response and genotype distribution in different areas and races of China

Hepatitis C virus (HCV) heterogeneity accounts for the failure of effective vaccine development and the lack of successful anti-viral therapy in some patients. Little is known about the immune response to HCV peptides and the region or race specific genotypes in China. The objective of this study was to characterize HCV antibody immune response to HCV peptides and HCV genotypes in different regions and races of China. A total of 363 serum samples were collected from HCV carriers in 6 regions in China. The immune response to HCV peptides was evaluated by ELISA. HCV genotypes were examined using nested RT-PCR. We found that the anti-HCV antibody neutralization rates were significantly different among the serum samples from different areas or from different races in the same area. For samples from Tibet and Sinkiang, the rates of neutralization by HCV peptides were only 3.2% and 30.8%, respectively. The genotypes of samples from Tibet and Sinkiang were apparently heterogeneic and included type I, II, III and multiple types (I/II/III, I/II, I/III, II/III). One specific sample with multiple-genotype (I/II/III) HCV infection was found to consist of type I, II, III, II/III and an unclassified genotype. These studies indicate that the anti-HCV antibody immune response to HCV peptides varied across regions and among races. The distribution of HCV genotypes among Tibetans in Tibet and Uighurs in Sinkiang was different from that in the inner areas of China. In addition, a "master" genotype, type II, was found to exist in HCV infection with multiple HCV genotypes.

Hepatitis C virus genotype 1b as a risk factor for hepatocellular carcinoma development: a meta-analysis

BACKGROUND/AIMS

Hepatitis C virus (HCV) is a known risk factor for hepatocellular carcinoma (HCC), but whether the risk varies among patients infected with different HCV genotypes is still controversial. We performed a meta-analysis to clarify whether the genotype 1b is associated with a higher risk of HCC than other genotypes.

METHODS

We identified 57 relevant papers through a literature search to December 2007 but, since age could represent a major confounder, we focused the meta-analysis on the 21 studies presenting age-adjusted risk estimates for HCV genotype 1b vs. other genotypes. We used random-effects models with the DerSimonian-Laird method and assessed heterogeneity between studies and publication bias.

RESULTS

Patients infected with HCV genotype 1b have almost double the risk to develop HCC than those infected with other genotypes (Relative Risk (95% Confidence Intervals) = 1.78(1.36-2.32)). The pooled risk estimate was somewhat lower when we restricted the analysis to the eight studies conducted in patients with liver cirrhosis (1.60;1.07-2.39) or considering the 36 studies presenting only crude data (1.63;1.30-2.06). In seven studies excluding patients with liver cirrhosis, the RR (95% CI) increased to 2.46(1.69-3.59).

CONCLUSIONS

This meta-analysis suggests that HCV genotype 1b plays an important role in HCC development, especially in patients with early stage liver disease.

Factors associated with adherence to combination therapy of interferon and ribavirin for patients with chronic hepatitis C: importance of patient's motivation and physician's treatment experience

BACKGROUND/AIMS

Adherence to combination therapy with interferon (IFN) or pegylated IFN plus ribavirin for chronic hepatitis C patients is important for a better virological response. However, the impact of the patient's treatment experience and treatment centre on adherence to combination therapy has not been fully analysed. In this prospective study, we analysed the factors that might have an effect on adherence to therapy in patients who had initial or retreatment IFN therapy.

PATIENTS AND METHODS

We consecutively enrolled 363 patients with chronic hepatitis C; 221 were IFN naïve and 142 were undergoing retreatment. The mean ages of the naïve and retreatment groups were 54.8 and 55.7 years respectively. IFN alpha-2b was administered daily for 2 weeks, followed by three times per week for 22 weeks, while ribavirin was administered daily. We evaluated the tolerability and response to combination therapy and analysed its relevant factors.

RESULTS

Of the 363 patients, 189 (52%) achieved 80% adherence. The multivariate logistic regression analysis revealed that retreatment, centre with more patients treated, patient age (<55 years), male, genotype 2 and dosage of IFN per weight (<0.13 million units/kg) were associated with achievement of 80% adherence to combination therapy. Accordingly, the achievement of 80% adherence was more frequent in the retreatment (62%) than that in the naïve group (46%) (P<0.01) and in centres with more patients treated (57%) than in those with less patients treated (46%) (P=0.03).

CONCLUSION

The present data suggest that the patient's motivation and the physician's treatment experience may be important for a better adherence to combination therapy for patients with chronic hepatitis C.

The longitudinal quantitative assessment by transient elastography of chronic hepatitis C patients treated with pegylated interferon alpha-2b and ribavirin

The aim of this study was to assess the association between liver stiffness measured by transient elastography (FibroScan) and the efficacy of pegylated interferon alpha-2b plus ribavirin combination treatment for patients with chronic hepatitis C virus (HCV) infection. We prospectively studied 145 Japanese patients with chronic HCV infection. FibroScan was done at baseline, at the end of treatment, and at 48 and 96 weeks after the end of treatment. The FibroScan values were significantly decreased for sustained virological response (SVR) patients (the mean rate of change; -16.2%, -32.2% and -43.5%) in comparison with non-SVR patients (-7.2%, -2.1% and +17.3%) at the end of treatment (P=0.0127), and 48 weeks (P<0.0001) and 96 weeks (P<0.0001) after the end of treatment. Among the non-SVR patients, the FibroScan values were significantly decreased for patients with biochemical response (BR) (-17.9%, -30.0% and -27.1%) in comparison with non-BR (-4.1%, +6.4% and +30.6%) at the end of treatment (P=0.0270), and 48 weeks (P<0.0001) and 96 weeks (P<0.0001) after the end of treatment. The FibroScan values may predict a progressively better clinical outcome for patients with successful virological and biochemical responses.

A randomized study of extended treatment with peginterferon alpha-2b plus ribavirin based on time to HCV RNA negative-status in patients with genotype 1b chronic hepatitis C

OBJECTIVES

The treatment of patients with hepatitis C virus (HCV) genotype 1 with peginterferon plus ribavirin treatment for more than 48 weeks demonstrated high sustained virological response (SVR) rates. Although many studies extended the duration of therapy from 48 weeks to 72 weeks, the optimal duration has not yet been determined.

METHODS

A total of 113 genotype 1b patients with high viral load were randomized at baseline to the standard (n=56) or extended (n=57) treatment group. The standard group patients received 48 weeks of peginterferon plus ribavirin treatment. In the extended group, the treatment was performed for 44 weeks after patients became negative for HCV RNA (total duration 48-68 weeks).

RESULTS

The SVR rate of the standard and extended group was 36% (20 of 56) and 53% (30 of 57; P=0.07). However, the extended group patients who became negative for HCV RNA between weeks 16 and 24 had a significantly higher SVR rate (78%; 7 of 9) than that of standard group (9%, 1 of 11; P=0.005). The predictive factors for the SVR were the treatment regimen (the standard vs. extended treatment) and the time to HCV RNA negative-status.

CONCLUSIONS

The extended treatment significantly increased the SVR rate in patients who were HCV RNA negative at 16-24 weeks.

Four-week pegylated interferon α-2a monotherapy for chronic hepatitis C with genotype 2 and low viral load: A pilot, randomized study

AIM: To assess the efficacy and advantages of 4-wk pegylated interferon α-2a (peg-IFN-α2a) monotherapy for chronic hepatitis C patients with strong predictors of sustained virologic response (SVR).

METHODS: Patients (n = 33) with genotype 2 and low viral load (< 100 KIU/mL), who became HCV RNA negative after 1 wk of IFN treatment, were randomly allocated to receive a 4- or 12-wk treatment course at a ratio of 2:1, respectively, with a subsequent 24-wk follow-up period. Peg-IFN-α2a was administered subcutaneously at a dose of 180 μg or 90 μg once weekly. SVR was defined as absence of serum HCV RNA at the end of the follow-up period.

RESULTS: All patients completed the treatment schedule, and more than half were symptom-free during the treatment. In the 4-wk treatment group, 20 of 22 (91%) patients achieved SVR. Two patients relapsed, but achieved SVR following re-treatment with peg-IFN-α2a alone. In the 12-wk treatment group, 11 of 11 (100%) patients attained SVR.

CONCLUSION: Our results show that a 4-wk course of peg-IFN-α2a monotherapy can achieve a high SVR rate in “IFN-sensitive” patients, without negatively affecting outcome.

Sequence variation in hepatitis C virus nonstructural protein 5A predicts clinical outcome of pegylated interferon/ribavirin combination therapy

A substantial proportion of hepatitis C virus (HCV)-1b-infected patients still do not respond to interferon-based therapy. This study aims to explore a predictive marker for the ultimate virological response of HCV-1b-infected patients treated with pegylated interferon/ribavirin (PEG-IFN/RBV) combination therapy. Nonstructural protein 5A (NS5A) sequences of HCV in the pretreated sera of 45 patients infected with HCV-1b were analyzed. The mean number of mutations in the variable region 3 (V3) plus its upstream flanking region of NS5A (amino acid 2334-2379), referred to as IFN/RBV resistance-determining region (IRRDR), was significantly higher for HCV isolates obtained from patients who later achieved sustained virological response (SVR) by PEG-IFN/RBV than for those in patients undergoing non-SVR. The receiver operating characteristic curve analysis estimated six mutations in IRRDR as the optimal threshold for SVR prediction. Indeed, 16 (76%) of 21 SVR, but only 2 (8%) of 24 non-SVR, had HCV with six or more mutations in IRRDR (IRRDR > or = 6) (P < 0.0001). All of 18 patients infected with HCV of IRRDR of 6 or greater examined showed a significant (> or =1 log) reduction or disappearance of serum HCV core antigen titers within 24 hours after initial dose of PEG-IFN/RBV, whereas 10 (37%) of 27 patients with HCV of IRRDR of 5 or less did (P < 0.0001). The positive predictive value of IRRDR of 6 or greater for SVR was 89% (16/18; P = 0.0007), with its negative predictive value for non-SVR being 81% (22/27; P = 0.0008).

CONCLUSION

A high degree (> or =6) of sequence variation in IRRDR would be a useful marker for predicting SVR, whereas a less diverse (< or =5) IRRDR sequence predicts non-SVR.

Investigation of putative multisubtype hepatitis C virus infections in vivo by heteroduplex mobility analysis of core/envelope subgenomes

The frequency that multiple different subtypes of hepatitis C virus (HCV) simultaneously infect a given individual is controversial. To address this question, heteroduplex mobility analysis (HMA) of portions of the HCV core and envelope 1 region was optimized for sensitive and specific detection of mixtures of HCV genomes of different genotype or subtype. Using the standard HCV genotyping approach of 5'-untranslated region (UTR) analysis, 28 of 374 (7.5%) chronic hepatitis C research subjects were classified as having either multiple-subtype HCV infections (n = 21) or switching HCV subtypes over time (n = 7), the latter pattern implying viral superinfection. Upon retesting of specimens by HMA, 25 of 28 multiple-subtype results could not be reproduced. All three patients with positive results were injection drug users with potential multiple HCV exposures. To address the hypothesis of tissue sequestration of multiple-subtype HCV infections, liver (n = 22), peripheral blood mononuclear cell (n = 13), perihepatic lymph node (n = 16), and serum (n = 19) specimens from 23 subjects with end-stage hepatitis C were collected and analyzed by the HMA technique. Whereas 5'-UTR results implicated mixed-subtype HCV infections in 2 subjects, HMA testing revealed no evidence of a second HCV subtype in any tissue compartment (0 of 70 compartments [0%]) or within any given subject (0 of 23 subjects [0%]). In summary, a large proportion of mixed-genotype and switching-genotype patterns generated by 5'-UTR analysis were not reproducible using the HMA approach, emphasizing the need for additional study.

Increased soluble IL-2 receptor levels during interferon and ribavirin treatment are associated with a good response in genotype 2a/2b patients with chronic hepatitis C

OBJECTIVES

Serum levels of soluble interleukin-2 receptor (sIL-2R) are known to serve as a marker for the activation of T lymphocytes. We measured serum levels of sIL-2R in patients with chronic hepatitis C (CHC) during interferon (IFN)-based treatment to determine the correlation between those levels and therapeutic efficacy, and to clarify whether there is a difference in the activation of T lymphocytes among HCV genotypes after the treatment.

METHODS

Forty-four patients received IFN-alpha2b monotherapy (group IFN-M), whereas 82 patients received the combination therapy with IFN-alpha2b and ribavirin (group IFN+R). We measured serum sIL-2R levels in these patients before (T0) and 2 weeks (T2) after the treatment.

RESULTS

The sustained virologic response rates in genotype 2a/2b patients were significantly higher than those in genotype 1b patients in both groups (P<0.005). In sustained virologic responders, sIL-2R levels at T2 were significantly higher than those at T0 in both groups (P<0.001). In nonresponders, sIL-2R levels at T2 were not different from those at T0 in group IFN-M, but were significantly higher than those at T0 in group IFN+R (P=0.0072). In genotype 1b patients, sIL-2R levels at T2 were not different from those at T0 in group IFN-M, but were significantly higher than those at T0 in group IFN+R (P=0.0064). In genotype 2a/2b patients, sIL-2R levels at T2 were significantly higher than those at T0 in both groups (P<0.0005).

CONCLUSION

These findings suggest that the activation of T lymphocytes after IFN-based treatment contributes to a high-sustained virologic response rate, especially in genotype 2a/2b patients.

Development of an improved genotyping assay for the detection of hepatitis C virus genotypes and subtypes in Pakistan

A new genotyping system was established for the specific detection of HCV genotypes 1a, 1b, 1c, 2a, 2b, 2c, 3a, 3b, 3c, 4a-h, 5a and 6a during the course of this study. The system is based on entire core region and a part of 5' noncoding region (5'NCR) with genotype-specific primers. Genotype-specific primers were designed on the basis of 114 HCV isolates. Serum samples with known genotypes were used as positive controls to validate the assay developed and to generate PCR band patterns. Band patterns generated from the clinical serum samples from HCV patients were compared to the patterns produced from these control samples. In addition, the type-specific bands were sequenced from the test patients and control clinical samples to validate further the test results. To determine sensitivity and specificity of the assay, a total 260 samples were analyzed simultaneously by this HCV genotyping method and that developed by Ohno and Murex HCV Serotyping 1-6 Assay. The system showed 79.2% concordance with Ohno's system and 65.38% with serotyping system. Samples with discordant results were sequenced and their genotypes were determined by molecular evolutionary analysis. The data indicate that the method described in this study may offer better sensitivity and specificity for the detection directly of HCV genotypes present at low levels in HCV patient samples.

Prediction of efficient virological response to pegylated interferon/ribavirin combination therapy by NS5A sequences of hepatitis C virus and anti-NS5A antibodies in pre-treatment sera

A considerable number of patients infected with Hepatitis C virus subtype 1b (HCV-1b) do not respond to pegylated interferon/ribavirin combination therapy. In this study we explored a useful factor(s) to predict treatment outcome. A total of 47 HCV-1b-infected patients were treated with pegylated interferon/ ribavirin for 48 weeks. Sera of the patients were examined for the entire NS5A sequence of the HCV genome, HCV RNA titers and anti-NS5A antibodies. According to their responses, the patients were divided into two groups, early viral responders who cleared the virus by week 16 (EVR[16w]) and those who did not (Non-EVR[16w]). The mean number of mutations in the V3 region (aa 2356 to 2379) or that in the V3 region plus its N-terminally flanking region, which we refer to as interferon/ribavirin resistancedetermining region (IRRDR; aa 2334 to 2379), of NS5A obtained from the pretreatment sera was signifi-cantly larger for EVR(16w) compared with Non-EVR(16w). Moreover, HCV-1b isolates with > or =5 mutations in V3 or those with > or =6 mutations in IRRDR were almost exclusively found in EVR(16w). Also, the presence of detectable levels of anti-NS5A antibodies in the pretreatment sera was closely associated with EVR(16w). In conclusion, a high degree of sequence variation in V3 (> or =5) or IRRDR (> or =6) and the presence of detectable levels of anti-NS5A antibodies in the pretreatment sera would be useful factors to predict EVR(16w). On the other hand, a less diverse sequence in V3 (< or =4) or IRRDR (< or =5) together with the absence of detectable anti-NS5A antibodies could be a predictive factor for Non-EVR(16w).

Performance characteristics of a real-time RT-PCR assay for quantification of hepatitis C virus RNA in patients with genotype 1 and 2 infections

BACKGROUND

Polymerase chain reaction (PCR) methods play an essential role in providing data relating to diagnosis, monitoring and treatment of hepatitis C virus (HCV) infection. The real-time reverse transcription PCR (RT-PCR) assay is an established and promising tool in terms of quantifying HCV RNA for clinical application. This study aimed to evaluate the performance characteristics of a real-time RT-PCR-based test in a clinical setting.

METHODS

Validation and reproducibility tests were performed using a standard panel. Sera from 197 chronic HCV patients were analyzed by the real-time RT-PCR assay and the results were compared with the Versant bDNA3.0 assay (bDNA3.0).

RESULTS

The real-time RT-PCR assay showed an acceptable linear response (r2=0.989-0.995) in the serial dilutions regarding genotypes 1b, 2a, 2b and 1b+2a. HCV viral loads were quantifiable in all 197 patients (100%) by the real-time RT-PCR assay and in 194 (98.5%) by the bDNA3.0. HCV RNA quantification values measured by the real-time RT-PCR and bDNA3.0 assays were positively correlated (Pearson's correlation coefficient r=0.734, p<0.001). The real-time RT-PCR assay values were on average 0.13 logs higher than the bDNA3.0 results. The correlation coefficients with genotypes 1b, 2a, 2b and mixed were 0.737, 0.711, 0.791 and 0.766, respectively (p<0.01).

CONCLUSIONS

The real-time RT-PCR assay showed comparable performance with bDNA3.0 regarding quantification of HCV viral loads with genotype 1 and 2 HCV infections.

Liver disease in hepatitis C virus carriers identified at blood donation and their outcomes with or without interferon treatment: Study on 1019 carriers followed for 5-10 years

AIM

To portray liver disease and project outcomes in carriers of hepatitis C virus (HCV) in the general population.

METHODS

Liver disease was evaluated in 1019 individuals who were found with HCV infection at blood donation, and they were followed for 5-10 years with or without receiving interferon (IFN).

RESULTS

At baseline, chronic hepatitis was detected in 529 (51.9%) HCV carriers and more frequently in men than in women (62.6% [299/478]vs 42.5% [230/541], P < 0.01); cirrhosis was diagnosed in five (0.5% [three men included]) and hepatocellular carcinoma (HCC) in one (0.1% [man]). Of the carriers who were followed for 5 years or longer, loss of HCV-RNA from serum was achieved in 61 (31.0%) of the 197 treated with interferon (IFN) and only one of the 211 (0.5%) without IFN (P < 0.0001). HCC developed in 14 carriers including six ofthe 211 (2.8%) without IFN and eight of the 197 (4.1%) with IFN (six non-responders included). Follow ups of the 949 carriers identified age (P < 0.002), male gender (P < 0.01) and cirrhosis at the baseline (P < 0.0001) as factors contributing to the development of HCC. Cumulative incidence rates of HCC during 10 years among carriers found with chronic hepatitis increased in parallel with the age at the baseline.

CONCLUSION

Identification of HCV carriers in the general population and treating those indicated with IFN would help decrease the development of HCC and lift its medical, as well as economic, burdens off society.

Effect of lactoferrin in patients with chronic hepatitis C: combination therapy with interferon and ribavirin

OBJECTIVES

Lactoferrin has been reported to inhibit hepatitis C virus (HCV) infection in cultured human hepatocytes and HCV viremia in patients with chronic hepatitis C (CHC). The aim of this study was to evaluate the effect of combined triple therapy of lactoferrin, interferon and ribavirin in patients with CHC.

METHODS

A total of 111 Japanese patients with CHC were randomly assigned to a lactoferrin group (n = 50) and a control group (n = 61). The lactoferrin group was treated with lactoferrin for 8 weeks and then with lactoferrin, interferon and ribavirin for 24 weeks; the control group was treated with interferon and ribavirin for 24 weeks. Serum anti-lactoferrin antibody, clinical and laboratory measurement were determined.

RESULTS

The mean HCV RNA titer significantly decreased at the end of lactoferrin monotherapy. Sustained virological response to therapy was significantly higher (P < 0.05) in the lactoferrin responder group (55%) than in the control group (18%).

CONCLUSIONS

The results show that the decrease in HCV RNA titer by lactoferrin monotherapy contributes to the effectiveness of the combined therapy of interferon and ribavirin in patients with CHC. Lactoferrin is a potential useful adjunct treatment for patients with CHC.

Distribution of hepatitis C virus genotypes in patients with chronic hepatitis C infection in Western Turkey

OBJECTIVE

The primary aim of this study was to determine the recent distribution of various genotypes of hepatitis C virus (HCV) in patients with chronic HCV infection in Western Turkey. Additional objectives were to determine whether there are any associations of genotype with gender and age, and to determine the nucleotide similarities and risk factors of non-1 HCV genotypes.

METHODS

Serum samples from 345 patients (176 male, 169 female; mean age 53.3+/-12.7 years, range 10-81 years) with chronic HCV infection were analyzed in this study. Viral genotypes were determined by a restriction fragment length polymorphism (RFLP)-based in-house assay. To confirm genotypes for the samples with band patterns other than genotype 1, the 5' UTR was amplified and sequenced.

RESULTS

Genotype 1 was observed in 335 of the 345 patients (97.1%). Of these, 34 patients showed infection with subtype 1a (9.9%) and 301 with subtype 1b (87.2%). Genotypes 2, 3, and 4 were determined in 0.9%, 1.4%, and 0.6% of the patients, respectively. Patients infected with type 1 were significantly older than patients infected with non-1 genotypes; however no significant differences were recorded in gender distribution.

CONCLUSIONS

Genotypes other than genotype 1 are quite rare; these are possibly acquired in other countries. Turkish patients with chronic hepatitis C still represent a rather homogenous group with genotypic diversity encountered rarely.

Factors influencing treatment efficacy of 24-week combination therapy with interferon alpha-2b plus ribavirin for chronic hepatitis C

The efficacy of a combination therapy of interferon (IFN) alpha-2b plus ribavirin (RBV) in chronic hepatitis C, and the factors contributing to efficacy, were investigated. One hundred eighty-six cases were enrolled in this study and treated with a combination of IFN alpha-2b plus RBV. IFN alpha-2b was administered at 6-10 mega-units daily for 2-4 weeks and three times per week for 20-22 weeks, in combination with oral intake of RBV at 600 or 800 mg for 24 weeks. Rates of sustained virological response (SVR) were 34.9% in serogroup 1 (SG1) and 82.5% in SG2. SVR rates in cases with both drugs discontinued, reduced, and unchanged were 4.2%, 40%, and 42.7% in SG1 and 42.9%, 76.9%, and 91.9%, in SG2. In terms of the total RBV dose per kilogram body weight, SVR rates were 14.3% and 46.2% with <1600 mg, 36.2% and 91.7% with 1600-2000 mg, and 62.1% and 95% with > or =2000 mg in SG1 and SG2, respectively. Total doses of RBV per body weight and negative HCV RNA at 8 weeks were the significant factors contributing to SVR in SG1 cases. These results indicate that it was critical to tailor the doses of RBV and IFN to the individual. To improve the rate of SVR, it is necessary to make efforts, where possible, not to discontinue drug use or reduce the drug dose.

Complexity of the HVR-1 quasispecies and disease activity in patients with hepatitis C

BACKGROUND

Hepatitis C virus (HCV) easily undergoes genomic changes, especially in the hypervariable region (HVR) in the N-terminus of the E2/NS1 region. The quasispecies nature of HCV may have important biological implications in relation to viral persistence; however, the relationship between disease activity of chronic HCV infection and development of the genomic complexity have yielded conflicting results. We explored the changes in the complexity of the HVR-1 in the natural course of chronic HCV infection with and without elevation of serum alanine transaminase (ALT) levels.

MATERIALS AND METHODS

Ten patients with chronic hepatitis C proven by liver biopsy, who showed persistent elevation of the serum ALT levels, and 15 patients with chronic HCV infection and persistently normal serum ALT levels (PNAL) were enrolled in this study. The number of the HCV quasispecies was determined twice for each patient at an interval of mean 2.5 years by fluorescence single-strand conformation polymorphism and sequence analysis.

RESULTS

There was no significant difference in the changes in the number of quasispecies during the follow-up period between chronic hepatitis C and PNAL. There was also no significant difference in the change in the number of variable nucleotides sites between the two groups. In these patients, the number of quasispecies and the diversity of HVR-1 were correlated with platelet counts and serum hyaluronic acid levels previously shown to be associated with disease progression.

CONCLUSION

Our results suggested that the disease activity is not always related to the generation of the HVR-1 quasispecies complexity.