Background: New treatments for HCV are significantly more effective than past treatments. They utilize direct acting antiviral drugs (DAA) and many do not include interferon. The goal of treatment is to achieve a sustained virological response (SVR). An SVR is indicated by the absence of detectable HCV RNA in blood 12 weeks after the end of treatment (EOT); this is called SVR12. The researchers recently investigated outcomes of 514 non-liver transplant (LT) patients and 43 LT patients who initiated treatment between Dec 2013 and June 2014. Several patients developed increased levels of markers of autoimmune processes and/or experienced a bacterial infection. Investigators at other institutions recently reported evidence that DAA treatment enhances immune cell activation. The combination of the investigators' observations and the observations of others indicates that a detailed investigation is needed to understand the events leading to increased immune cell activity and to determine the factors that may increase the risk of serious adverse events.