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Hepatitis C virus E2 and NS5A region variability during sequential treatment with two interferon-alpha preparations
Emanuele Durante Mangoni1, Daniel M Forton, Giuseppe Ruggiero
1Department of Medicine A, Faculty of Medicine, Imperial College of Science, Technology and Medicine, St Mary's Campus-QEQMW, London, United Kingdom.
Journal of Medical Virology
|March 12, 2003
Summary
Hepatitis C virus (HCV) quasispecies in the HVR-1 region evolve differently in patients responding to interferon treatment compared to non-responders. Specific amino acid conservation in HVR-1 and NS5A variability are key to treatment outcomes.
Area of Science:
- Virology
- Immunology
- Genetics
Background:
- Hepatitis C virus (HCV) genetic heterogeneity influences treatment response.
- Interferon-based therapies are standard for HCV, but patient responses vary.
- Understanding viral evolution during treatment is crucial for optimizing therapy.
Purpose of the Study:
- To investigate the genetic variation of HCV hypervariable region 1 (HVR-1) and NS5A quasispecies.
- To correlate HCV genetic patterns with treatment outcomes in patients receiving interferon therapy.
- To identify specific viral sequences or mutations associated with treatment response.
Main Methods:
- Cloning and sequencing of HVR-1 and NS5A regions from 12 HCV-1b infected patients.
- Analysis of viral quasispecies complexity, diversity, and substitution ratios.
- Amino acid sequence analysis focusing on key viral epitopes and the Interferon Sensitivity Determining Region (ISDR).
Main Results:
- Responder-relapser patients showed decreased HVR-1 genetic complexity and diversity during treatment, especially with lymphoblastoid alpha-interferon.
- Non-responders exhibited a broadening of HVR-1 quasispecies.
- Highly conserved amino acids (G406, Q409) in a major viral epitope were maintained throughout treatment.
- Responder-relapsers had higher NS5A mutation frequencies; lymphoblastoid interferon selected for intermediate ISDR sequences, while recombinant-2b favored conserved ISDR sequences.
- Variability upstream of the ISDR correlated with treatment response.
Conclusions:
- HCV HVR-1 quasispecies evolution patterns correlate with clinical response to interferon therapy.
- Conservation of specific amino acids in HVR-1 may be a target for immune-based therapies.
- NS5A variability, not just the ISDR, likely plays a role in interferon treatment outcomes.
- Different alpha-interferon preparations may have distinct effects on HCV quasispecies dynamics.