Polymorphisms near the interleukin-28B (IL28B) or interferon lambda 3 (IFN-λ3) gene are strongly associated with spontaneous clearance.4, 5 Treatment responses during acute HCV are high,6 but treatment is costly and may lead to adverse events. As such, the benefits of early treatment

must be balanced against the potential for spontaneous clearance. Identifying factors predicting spontaneous clearance is important for enhancing clinical decision-making around early therapeutic intervention and may also provide insight into the mechanisms involved in spontaneous clearance. During treatment for hypoxia-inducible factor cancer chronic HCV, the expression level of interferon-stimulated genes (ISGs) in the liver is associated with the probability of achieving a sustained virological response (SVR).7-11 Patients with high baseline hepatic ISG expression have a lower chance of SVR with interferon-based therapy. However, repeated liver biopsies are invasive and find more impractical, so serum biomarkers have been investigated. Interferon-gamma (IFN-γ)-inducible protein-10 (IP-10, CXCL10) is a chemokine produced by a variety of cells, including hepatocytes, attracting T lymphocytes, natural killer cells, and monocytes.12 IP-10 is interferon-inducible and is produced by hepatocytes upon HCV infection,13 with circulating plasma IP-10 levels correlating with intrahepatic IP-10 messenger RNA (mRNA) expression14 in chronic

HCV infection. Similar to hepatic ISG expression, circulating IP-10 levels are predictive of treatment outcome. High pretreatment IP-10 levels are associated with reduced rates of SVR during pegylated (PEG)-IFN/ribavirin (RBV) treatment of chronic HCV14-19 and HCV/HIV (human immunodeficiency virus) medchemexpress coinfection.20, 21 Further, when pretreatment IP-10 levels are combined with IL28B genotype, the predictive value for discrimination between SVR and nonresponse is improved, especially in those with unfavorable IL28B

genotypes.17, 18 However, there are limited data on factors associated with high levels of IP-10 and the impact of IP-10 levels on spontaneous clearance. In this study, factors associated with IP-10 levels at the time of acute HCV detection were investigated. Additionally, we sought to evaluate the utility of plasma IP-10 levels at the time of acute HCV detection as a predictor of spontaneous clearance. HCV, hepatitis C virus; IL28B, interleukin-28 gene; IP-10, IFN-γ-inducible protein-10; ISGs, interferon-stimulated genes; SNPs, single nucleotide polymorphisms; ROC, receiver operator characteristic. Data from three cohorts studying acute HCV were used for this study. The Australian Trial in Acute Hepatitis C (ATAHC) was a prospective study of recent HCV.6 The Hepatitis C Incidence and Transmission Study in prison (HITS-p) is an ongoing study of prison inmates at risk for acute HCV in correctional centers.22 The St. Luc Cohort, HEPCO study is a community-based study of people who inject drugs at risk for acute HCV.