Association between the IL28B genotype and hepatitis C viral kinetics in the early days of treatment with pegylated interferon plus ribavirin in HIV/HCV co-infected patients with genotype 1 or 4

Objectives To evaluate the effect of the interleukin 28B (IL-28B) genotype on hepatitis C virus (HCV) viral kinetics in the first 4 weeks from start of treatment with pegylated interferon plus ribavirin (PEG-IFN/RBV) in HIV/HCV co-infected patients. Methods HIV/HCV co-infected patients naive to PEG-IFN/RBV treatment were enrolled in a prospective study. HCV RNA plasma viral loads were measured at baseline and at weeks 1, 2 and 4 after commencement of treatment. Patients were grouped by HCV genotype (genotype 1/4 versus 3) and by IL-28B genotype (CC versus non-CC). Differences in viral load reduction were evaluated by IL-28B genotype between baseline, week 1, week 2 and week 4. Results One hundred and nineteen HIV/HCV patients were included in the study. HCV patients with genotype 1/4 and bearing the IL-28 CC genotype showed the greatest reductions in HCV RNA plasma levels between baseline and weeks 1 (B-1), 2 (B-2) and 4 (B-4) than did those with non-CC genotypes (B-1: 1.06 ± 0.89 versus 0.48 ± 0.48 log IU/mL, P = 0.009; B-2: 1.36 ± 0.72 versus 0.77 ± 0.66 log IU/mL, P = 0.01; and B-4: 1.91 ± 0.64 versus 1.38 ± 0.96 log IU/mL, P = 0.03). However, differences between weeks 1 and 2 (W1-2) and between weeks 2 and 4 (W2-4) were not associated with the IL-28B genotype (W1-2: CC 0.48 ± 0.42 versus non-CC 0.38 ± 0.38 log IU/mL, P = 0.62; W2-4: CC 0.32 ± 0.23 versus non-CC 0.39 ± 0.31 log IU/mL, P = 0.67). No differences in decline of HCV RNA viral load were found in HCV genotype 3 patients. Conclusions The IL-28B genotype impacts on viral kinetics during the first week of treatment with PEG-IFN/RBV in patients with HCV genotype 1/4.