Association of genetic variation in IL28B with hepatitis C treatment-induced viral clearance in the Chinese Han population.

BACKGROUND: Genome-wide association studies have recently shown that the rs12979860 polymorphism in IL28B is associated with the response to chronic hepatitis C treatment. The aim of this study was to investigate whether rs12979860 could be used as a predictive marker for end-of-treatment response (ETR) or sustained virological response (SVR) in the Chinese Han population. METHODS: The rs12979860 genotype was detected in 259 individuals infected with HCV by DNA sequencing. Among them, 120 patients were administered complete pegylated interferon-α and ribavirin combination therapy and 92 patients were followed for 24 weeks after the cessation of treatment and were divided into different groups according to outcomes of treatment. RESULTS: The rs12979860 genotype CC was the primary genotype (87.64%, 227/259) and genotype TT was found in only one individual within this cohort. The patients with the rs12979860 genotype CC had higher rates of ETR (P=0.0044) and SVR (P=0.0046) than the patients with N-CC (CT or TT). In multivariate analyses, the rs12979860 genotype CC was associated with a substantial difference in rates of achieving ETR (odds ratio [OR] 8.983, 95% confidence interval [CI] 2.173-37.145; P=0.0024) and SVR (OR 24.298, 95% CI 2.27-259.90; P=0.0083). CONCLUSIONS: This study demonstrated for the first time that the rs12979860 variation in IL28B could be a predictor of ETR and SVR in Chinese Han patients infected with HCV. The high frequency of the rs12979860 genotype CC might explain why the SVR rate is higher than that of the average global population.

Characterization of the specific CD4+ T cell response against the F protein during chronic hepatitis C virus infection.

BACKGROUND: The hepatitis C virus (HCV) Alternate Reading Frame Protein (ARFP or F protein) presents a double-frame shift product of the HCV core gene. We and others have previously reported that the specific antibodies against the F protein could be raised in the sera of HCV chronically infected patients. However, the specific CD4(+) T cell responses against the F protein during HCV infection and the pathological implications remained unclear. In the current study, we screened the MHC class II-presenting epitopes of the F protein through HLA-transgenic mouse models and eventually validated the specific CD4(+) T cell responses in HCV chronically infected patients. METHODOLOGY: DNA vaccination in HLA-DR1 and-DP4 transgenic mouse models, proliferation assay to test the F protein specific T cell response, genotyping of Chronic HCV patients and testing the F-peptide stimulated T cell response in the peripheral blood mononuclear cell (PBMC) by in vitro expansion and interferon (IFN)- γ intracellular staining. PRINCIPAL FINDINGS: At least three peptides within HCV F protein were identified as HLA-DR or HLA-DP4 presenting epitopes by the proliferation assays in mouse models. Further study with human PBMCs evidenced the specific CD4(+) T cell responses against HCV F protein as well in patients chronically infected with HCV. CONCLUSION: The current study provided the evidence for the first time that HCV F protein could elicit specific CD4(+) T cell response, which may provide an insight into the immunopathogenesis during HCV chronic infection.

Assessment of specific antibodies to F protein in serum samples from Chinese hepatitis C patients treated with interferon plus ribavarin.

The hepatitis C virus (HCV) alternate reading frame protein or F protein of the HCV 1b genotype is a double-frameshift product of the HCV core protein. In order to assess the presence of antibodies specific for F protein and their clinical relevance in sera from HCV patients, we produced recombinant F protein and core protein of the HCV 1b genotype in Escherichia coli. An enzyme-linked immunosorbent assay was developed using purified recombinant HCV core, F protein, and a 99-residue synthetic F peptide (F99). The seroprevalences of anticore, anti-F protein, and anti-F99 synthetic peptide were 95%, 68%, and 36%, respectively, in 168 HCV patients. The prevalence of anti-F antibodies did not correlate with viral load, genotype, or alanine aminotransferase level. Interferon combination therapy induced a decline in the level of anti-F antibodies in 55 responders (P < 0.01). Thirteen responders (24%) lost their anti-F recombinant protein antibodies, and 17 (31%) lost their anti-F synthetic peptide antibodies, whereas no decrease was observed for the 17 nonresponders. These changes were significant between responders and nonresponders (P < 0.05). Meanwhile, no change was found in the anticore antibody titer of the 72 treated patients. The percentage of anti-F-protein-negative patients (15/15 [100%]) who achieved a sustained virological response (SVR) was higher than that of the anti-F-positive patients (70%) (P < 0.05). Based on these findings, HCV F protein elicits a specific antibody response other than the anticore protein response. Our data also suggest that the presence and level of anti-F antibody responses might be influenced by the treatment (interferon plus ribavirin) and associated with an SVR in Chinese hepatitis C patients.