There are no specific reasons to exclude any patients from this protocol (exception below for plasmapheresis and lymphapheresis, and genetic analysis of serum samples) as it does not entail significant risk to the patient or excessive clinical burden to the Liver Diseases Branch. Patients who resolve their chronic liver disease, such as patients with chronic hepatitis B who become negative for HBsAg or patients with chronic hepatitis C who become negative for HCV RNA will continue to be followed despite lack of apparent disease or disability. This is to document that clearance of these hepatitis viruses is, indeed, associated with resolution of the liver disease and lack of long-term adverse effects. Because there are data suggesting that chronic HBsAg carriers who become HBsAg-negative and patients with chronic hepatitis C whose liver disease becomes inactive, can still develop long-term consequences of these diseases (especially hepatocellular carcinoma), following such patients is important.