Relationship of interferon-γ-inducible protein-10 kDa with viral response in patients with various heterogeneities of hepatitis C virus genotype-4.

INTRODUCTION: The role of serum interferon-γ-inducible protein-10 kDa (IP-10) level in the treatment of chronic hepatitis C genotype-4 (HCV-4) and its various subtypes remains unknown. We aimed to study the impact of pretreatment IP-10 levels on the sustained viral response (SVR) in HCV-4 patients (n=64) undergoing peginterferon α-2a/ribavirin therapy.

PATIENTS AND METHODS: Pretreatment IP-10 levels and HCV-4 subtypes (4a=48.4%, 4d=39%, others=12.5%) were measured and correlated with treatment responses. Variables significantly associated with SVR on univariate analysis were included in a multivariate logistic regression model.

RESULTS: Patients with SVR had lower pretreatment IP-10 levels (462.4±282.7 vs. 840.1±490.6 pg/ml; P=0.002), but the levels were not significantly different in those with a rapid (P=0.245) or an early viral response (P=0.221). IP-10 levels were similar across all subtypes. The pretreatment level was significantly lower in subtype 4d patients with SVR (465.9±349.1) compared with non-SVR patients (904.9±532.1; P<0.001), but not when compared with genotype 4a patients (564.7±288.9 vs. 658.6±374.9, respectively; P=0.330). IP-10 levels [odds ratio (OR), 0.998; 95% confidence interval (CI): 0.996-0.999; P=0.006], low viremia (OR, 8.852; 95% CI: 1.244-63.03; P=0.029), and early viral response (OR, 4.162; 95% CI: 1.023-16.94; P=0.046) were independent predictors of SVR. Receiver operating characteristic curve analysis identified a threshold IP-10 level of 359 pg/ml (area under receiver operating characteristic curve, 0.737; sensitivity, 81.8%; specificity, 45.2; positive predictive value, 43.9%; negative predictive value, 82.6%) for SVR.

CONCLUSION: Pretreatment serum IP-10 level is a predictor for SVR in HCV-4-infected patients. The baseline IP-10 level is significantly lower in responders among HCV genotype-4d patients as compared with 4a patients.