HEPATITIS C

Analysis of the Plasma Proteome of patients with chronic Hepatitis C Infection undergoing treatment with Interferon alpha and Ribavirin, a Pilot Study



Abstract

Background & aims

Chronic hepatitis C infection is a worldwide healthcare burden. The only current effective treatment is combination therapy with interferon-a and ribavirin. It is effective in up to 50% of those infected with Hepatitis C virus genotype1. Identification of biomarkers which predict response to treatment would enable better selection of patients who would benefit from treatment. The aim is to identify potential biomarkers indicative of either responsiveness or resistance to treatment of chronic Hepatitis C infection

Methods

Three patients out of ten chronically infected with Hepatitis C virus genotype 1b who were to be treated with pegylated Interferon alpha and Ribavirin were selected for the pilot study. Samples were taken before treatment, day 14, and day 28 on treatment. The samples were subjected to both 1D PAGE and 2D electrophoresis and were compared using Progenesis Same Spots software.

Results

Differences in plasma proteins were found by 2D gel electrophoresis when patients were treated with interferon-a and ribavirin. Initial results identified several low molecular weight proteins that were differentially expressed in some patients; these were identified as haptoglobin splice-forms using electro-spray mass spectrometry.Analysis of albumin-depleted plasma found that two patients showed a considerable increase in a -80KDa protein in samples taken at days 14 and 28 of treatment. This molecular weight is higher than expected and may be due to binding to a moiety such as haem or aberrant processing.

Conclusion

Haptoglobin variants may prove useful biomarkers for identifying response to interferon-a and ribavirin or excessive haemolysis in response to this treatment.

Key words: HCV, Interferon, Haptoglobin, Biomarkers, Proteomic, Antiviral therapy

Introduction

In this largest study of hepatitis C genotypes identified in England to date, genotype 3a infections were almost twice as common as 1a. The relative decline in 1b infections was largely explained by a decline in the proportion of people born pre-1940 being genotyped; a finding also noted in the US China and France Comparing the population being genotyped to those newly identified as HCV positive indicated that those being genotyped, and probably considered for treatment, were older. Genotype 1b infections were associated with acquisition via blood transfusion prior to the introduction of donor screening, and therefore, will be expected to decline further.

Genotype 3a infections are associated with IDU in Europe. Although risk exposures were poorly reported, the majority of people tested for HCV in England are known to have injected illicit drugs. In this study, G3a was more common (and G1b less common) among younger birth cohorts and those first tested in drug centres, groups likely to have been exposed through injecting, suggesting that genotype 3a is the main circulating genotype in IDUs in England.

Our limited analysis of genotype by ethnicity strongly suggests that HCV genotypes in England vary by ethnicity, probably reflecting acquisition abroad. To confirm these findings we recommend that ethnicity is recorded in laboratory information systems.

Although the decline in G1b infections should reduce costs associated with treatment (due ...