Typing six major hepatitis C virus genotypes by polymerase chain reaction using primers derived from nucleotide sequences of the NS5 region

Hashimoto, Michie; Chayama, Kazuaki; Tubota, Akihito; Kobayashi, Masahiro; Saitou, Satoshi; Arase, Yasuji; Ikeda, Kenji; Kobayashi, Mariko; Nakano, Akemi; Takagi, Kimiko; Koike, Hiromi; Okamoto, K.; Handa, Hiroshi; Kumada, Hiromitsu

doi:10.1016/0928-4346(96)00257-5

Cited by 16 publications

(13 citation statements)

References 7 publications

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“…The efficacy of IFN treatment within a six-month course was poor in patients with HCV-genotype lb and a high level of serum HCVRNAof more than 1 mEq/ml. But genotype lb is the predominant genotype in Japan (17) and in manyEuropean (19) and Western countries (20), so a pressing need exists to develop an effective antiviral strategy against this genotype. Kasahara et al (7) reported that the therapeutic efficacy was found to increase with a high total dose of IFN and prolonged IFN.…”

Section: Resultsmentioning

confidence: 99%

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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.

et al. 1999

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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 lb 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-oc 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 One patient was withdrawn from the study due to IFN side effects.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-a 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 ofISDR 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 lb and a high level of serum HCV-RNA. (Internal Medicine 38: 461-466, 1999)

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Section: Resultsmentioning

confidence: 99%

“…During and after IFN therapy HCV-RNAlevels were examined by the reverse transcription, nested PCR (16). HCVgenotypes were classified by a PCR using a mixture of primers for the six subtypes knownto exist in Japan, as reported previously ( 17).…”

Section: Patien Tsmentioning

confidence: 99%

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.

et al. 1999

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“…Serum samples were obtained from 78 consecutive adult Japanese patients with chronic HCV genotype 1b infection (determined by polymerase chain reaction [PCR] using a genotype-specific primer set [Hashimoto et al, 1996]. Patients were followed up for more than 1 year without any antiviral or immunosuppressive therapy between December 1994 and April 1997.…”

Section: Materials and Methods Patients And Serum Samplesmentioning

confidence: 99%

Fluctuations of hepatitis C virus load are not related to amino acid substitutions in hypervariable region 1 and interferon sensitivity determining region

et al. 1999

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Hepatitis C virus (HCV) load is one of the most important predictive factors of response to interferon treatment. However, little is known about the mode and determinants of viremia. The mode of viremia was investigated in 78 patients with chronic HCV genotype 1b infection during 1-2 years follow up. Virus load, determined by a branched chain DNA amplification assay, was stable in 73 of 78 (93.6%) patients, whereas 5 (6.4%) showed marked fluctuation (from undetectable level to more than 10 Meq/ml) in viral titer. To study the mechanisms mediating fluctuations in viral titer, amino acid sequences of two regions were examined; hypervariable region (HVR) 1 and the interferon sensitivity determining region (ISDR). Multiple amino acid substitutions were observed in HVR 1 but no relationship was evident between substitutions and virus titers. In contrast, no amino acid substitutions were observed in the ISDR in any patients with stable virus titer during a follow-up period of 12-24 months (7-24 samples) or in one patient who was observed for 15 years. Interestingly, multiple amino acid substitutions in the ISDR appeared in only two of the five patients with marked titer fluctuation, when the virus decreased markedly. Alanine aminotransferase levels in these five patients correlated with viral load. The data suggest that amino acid substitutions in HVR1 and ISDR are not essential for changes in viral titer. Possible mechanisms of fluctuations of viral titer and amino acid substitutions in the ISDR accompanying marked reductions in viral load are discussed.

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“…HCV genotype was classified by PCR, using a mixture of primers for six subtypes known to exist in Japan, as reported previously. 18 …”

Section: Serum Hcv-rna Markermentioning

confidence: 97%

Efficacy of interferon monotherapy in young adult patients with chronic hepatitis C virus infection

et al. 2006

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Typing six major hepatitis C virus genotypes by polymerase chain reaction using primers derived from nucleotide sequences of the NS5 region

Cited by 16 publications

References 7 publications

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.

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.

Fluctuations of hepatitis C virus load are not related to amino acid substitutions in hypervariable region 1 and interferon sensitivity determining region

Efficacy of interferon monotherapy in young adult patients with chronic hepatitis C virus infection

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