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Hepatitis C in human immunodeficiency virus-coinfected patients: increased variability in the hypervariable envelope
K E Sherman1, C Andreatta, J O'Brien
1Department of Medicine and Pathology, University of Cincinnati Medical Center, OH, USA.
Insights
Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) coinfection leads to increased HCV E2/NS1 hypervariable region variability. This viral evolution may contribute to interferon resistance in coinfected patients.
Area of Science:
- Virology
- Immunology
- Genetics
Background:
- Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) coinfection is common.
- Understanding HCV genetic variability is crucial for treatment efficacy, particularly in coinfected individuals.
Purpose of the Study:
- To investigate nucleotide sequence variability in the HCV E2/NS1 hypervariable region in patients coinfected with HCV and HIV.
- To compare this variability with that observed in patients infected solely with HCV.
Main Methods:
- Sequencing of 91 clones from 10 HCV/HIV coinfected patients and 53 clones from 7 HCV-only patients.
- Analysis focused on the E2/NS1 hypervariable region (amino acids 384-414).
- Evaluation of synonymous/nonsynonymous amino acid changes and prediction of high-antigenicity sites.
Main Results:
- Significantly increased HCV RNA variability in coinfected patients compared to HCV-only patients (P < .05).
- Highest variability observed at specific amino acid sites (386, 397, 400, 402, 405, 407, 414).
- Nonsynonymous variations altered putative antigenic sites, with unique antigenic domains more frequent in coinfected individuals.
Conclusions:
- HCV/HIV coinfection promotes the accumulation of HCV envelope variants.
- Increased viral diversity may be linked to impaired viral clearance and interferon (IFN) resistance in coinfected patients.
Abstract:
Patients coinfected with the hepatitis C virus (HCV) and the human immunodeficiency virus (HIV) were studied with regard to nucleotide sequence variability in the E2/NS1 first hypervariable region of the HCV genome. The nucleotide variability within individual patients was compared to patients infected only with HCV. The proportion of predicted synonymous and nonsynonymous amino acid changes, and the relationship to putative high-antigenicity sites, were evaluated in the hypervariable envelope domain. Ninety-one clones from 10 patients with HCV/HIV coinfection were sequenced, following polymerase chain reaction (PCR) amplification of the hypervariable region. The control HCV group included 53 clones from 7 patients. Sequence analysis encompassed the region coding for amino acids 384 to 414. Consensus sequences from each patient were used as the internal standard for nonsynonymous amino acid codon variability. Cumulative proportional comparison at each amino acid site revealed increased variability in HCV RNA from patients with HCV/HIV coinfection versus HCV alone (P < .05). The greatest variability was observed at amino acids 386, 397, 400, 402, 405, 407, and 414, with >l0 percent clonal variation at these sites. Jameson-Wolf plots were used to predict putative high-antigenicity domains. Nonsynonymous clonal variation resulted in alteration of putative antigenic sites within the hypervariable region. All clones had at least one high-probability site. Clones with unique predicted antigenic domains were observed more frequently in HIV/HCV coinfected patients, and, independent of viral titer, were consistent with increased sequence variability. These data suggest an accumulation of envelope variants in the HCV/HIV coinfected patients, which could be related to ineffective viral clearance, and may help explain prior reports of interferon (IFN) resistance in this patient group.