The current standard of care (SoC) for chronic hepatitis C, i.e. the combination of a pegylated-interferon (PEG-IFN) with ribavirin (RBV), may activate underlying autoimmune conditions. Particularly, interferon (IFN) has been known to induce or exacerbate autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) in hepatitis C virus patients. We describe a severe, acute-onset antimitochondrial antibody (AMA)-M2 positive AIH appearing during the last weeks of SoC in a woman with chronic hepatitis C and no previous history of autoimmunity, and resolving on protracted steroids. In this context, the relevance of the characterization of the immunoglobulin isotype of portal plasma cells for a more appropriate diagnosis of autoimmune liver diseases can be emphasized.