Millions of people throughout the world are infected with hepatitis C virus (HCV), which can lead to cirrhosis of the liver and cancer.

Directly acting antiviral agents inhibit viral proteins and have been used to successfully treat HCV.

Unfortunately, antiviral therapy fails in some patients, resulting in a relapse of HCV.

A study published in the Journal of Clinical Investigation identifies a marker that can identify patients likely to have an HCV relapse after antiviral therapy.

Shyamasundaran Kottilil and colleagues at the NIH evaluated the immune response of HCV-infected individuals treated with antiviral agents.

Treated patients that had increased expression of type I interferon were more likely to remain HCV-free.

Patients unable to maintain a type I interferon response were more likely to have an HCV relapse.

This study provides a potential marker to identify patients prone to HCV relapse.

Moreover, these results suggest that type I interferon treatment in at-risk patients merits future study.

TITLE: Endogenous intrahepatic IFNs and association with IFN-free HCV treatment outcome