The novel ss469415590 variant predicts virological response to therapy in patients with chronic hepatitis C virus type 1 infection

Background A novel dinucleotide variant TT/G (ss469415590) has been associated with hepatitis C virus clearance. Aim To assess the role of the ss469415590 variant, compared with the known IL28B polymorphisms (rs8099917, rs12979860 and rs12980275) for predicting virological response to therapy in chronic hepatitis C, and its association with the CXCL10 chemokine serum levels - a surrogate marker of interferon-stimulated genes activation. Methods Multivariate analysis of factors predicting rapid and sustained virological response in 280 consecutive, treatment-naive, nondiabetic, Caucasian patients with chronic hepatitis C treated with peginterferon alpha and ribavirin. Results In hepatitis C virus genotype 1, the OR (95% CI) for rapid and sustained virological response for the wild-type ss469415590 TT was 9.88 (1.99-48.99) and 7.25 (1.91-27.51), respectively, similar to those found for rs12979860 CC [9.55 (1.93-47.37) and 6.30 (1.71-23.13)] and for rs12980275 AA [9.62 (1.94-47.77] and 7.83 (2.02-30.34)], but higher than for rs8099917 TT [4.8 (1.73-13.33) and 4.75 (2.05-10.98)]. In hepatitis C virus genotype 1, mean (SD) CXCL10 levels in patients with the TT/TT, TT/G and G/G variants were, respectively, 355.1 (240.6), 434.4 (247.4) and 569.9 (333.3) (P=0.04). In patients with genotypes 2 and 3 no significant association was found for TT/G with viral response. The predictive value of ss469415590 was stronger in patients with advanced fibrosis. Conclusions The novel IL28B variants at marker ss469415590 predict response to IFN alpha in chronic hepatitis C patients, especially in those with advanced fibrosis. Their determination may be superior to that of known IL28B variants for patient management using IFN-based regimens.