Effect of ribavirin on viral kinetics and liver gene expression in chronic hepatitis C.

OBJECTIVE: Ribavirin improves treatment response to pegylated-interferon (PEG-IFN) in chronic hepatitis C but the mechanism remains controversial. We studied correlates of response and mechanism of action of ribavirin in treatment of hepatitis C. DESIGN: 70 treatment-naive patients were randomised to 4 weeks of ribavirin (1000-1200 mg/d) or none, followed by PEG-IFNα-2a and ribavirin at standard doses and durations. Patients were also randomised to a liver biopsy 24 h before or 6 h after starting PEG-IFN. Hepatic gene expression was assessed by microarray and interferon-stimulated gene (ISG) expression quantified by nCounter platform. Temporal changes in ISG expression were assessed by qPCR in peripheral-blood mononuclear cells (PBMC) and by serum levels of IP-10. RESULTS: After 4 weeks of ribavirin monotherapy, hepatitis C virus (HCV) levels decreased by 0.5±0.5 log10 (p=0.009 vs controls) and ALT by 33% (p<0.001). Ribavirin pretreatment, while modestly augmenting ISG induction by PEG-IFN, did not modify the virological response to subsequent PEG-IFN and ribavirin treatment. However, biochemical, but not virological, response to ribavirin monotherapy predicted response to subsequent combination treatment (rapid virological response, 71% in biochemical responders vs 22% non-responders, p=0.01; early virological response, 100% vs 68%, p=0.03; sustained virological response 83% vs 41%, p=0.053). Ribavirin monotherapy lowered serum IP-10 levels but had no effect on ISG expression in PBMC. CONCLUSIONS: Ribavirin is a weak antiviral but its clinical effect seems to be mediated by a separate, indirect mechanism, which may act to reset IFN-responsiveness in HCV-infected liver.

Temperature rise after peginterferon alfa-2a injection in patients with chronic hepatitis C is associated with virological response and is modulated by IL28B genotype.

BACKGROUND & AIMS: Interferon treatment for chronic hepatitis C is associated with non-specific symptoms including fever. We aimed to determine the association of temperature changes with interferon antiviral activity. METHODS: 60 treatment-naïve patients with chronic hepatitis C (67% genotype 1/4/6, 33% genotype 2/3) were admitted to start peginterferon alfa-2a and ribavirin in a clinical trial. Temperature was measured at baseline and 3 times daily for the first 24h and the maximal increase from baseline during that time (ΔTmax) was determined. Serum HCV-RNA, interferon-gamma-inducible protein-10 (IP-10) and expression of interferon-stimulated genes (ISGs - CD274, ISG15, RSAD2, IRF7, CXCL10) in peripheral blood mononuclear cells (PBMCs) were measured at very early time points, and response kinetics calculated. The IL28B single nucleotide polymorphism, rs12979860, was genotyped. RESULTS: Temperatures rose by 1.2±0.8°C, peaking after 12.5h. ΔTmax was strongly associated with 1st phase virological decline (r=0.59, p<0.0001) and was independent of gender, cirrhosis, viral genotype or baseline HCV-RNA. The association with 1st phase decline was seen in patients with rs12979860CC genotype (r = 0.65, p <0.0001) but not in CT/TT (r = 0.13, p = 0.53) and patients with CC genotype had a higher DTmax (1.4 ± 0.8 C vs. 0.8 ± 0.6 +C, p = 0.001). DTmax was associated with 6- and 24-h induction of serum IP-10 and of PBMC ISG expression, but only in patients with rs12979860CC [corrected].ΔTmax weakly predicted early virological response (AUC=0.68, CI 0.49-0.88). CONCLUSIONS: Temperature rise following peginterferon injection is closely associated with virological response and is modulated by IL28B polymorphism, reflecting host interferon-responsiveness.