Antibodies Neutralizing Peginterferon Alfa during Retreatment of Hepatitis C

To the Editor: Peginterferons are widely used to treat chronic hepatitis C virus (HCV) infection, an important cause of liver cirrhosis and hepatocellular carcinoma.1–4 We describe a patient who did not have a virologic response to peginterferon and had a virtual absence of circulating peginterferon alfa-2a but had neutralizing antibodies against interferon alfa. A 38-year-old man with liver cirrhosis (Child–Pugh class A; score, 5) was referred to our hospital for evaluation of his chronic HCV infection. He had had no response to a 16-week course of treatment with peginterferon alfa-2b and ribavirin during the previous year. We enrolled him . . .