Patient description: A 53-year-old man presents with chronic HCV infection for the past 2 years. His past medical history is only significant for inguinal hernia surgery when he was 20 years old. He is on IFN (100 mg/week) plus RBV (400 mg/day) combination therapy for the past 9 months. Direct antiviral drugs were added to his treatment 6 months ago. His medical record shows previous positive HCV RNA tests as well as positive enzyme immunoassay for anti-HCV-antibodies. The recent biopsy was negative for hepatocellular carcinoma and was only remarkable for chronic inflammation compatible with a chronic viral hepatitis. There is no evidence of alcoholic liver disease, bleeding from esophageal varices, hemochromatosis, autoimmune hepatitis or metabolic liver disease. He is an alert male with no acute distress. His BP: 130/75, HR: 90/min and BMI: 27. His abdomen is soft with no ascites or tenderness. The lower extremities are normal with no edema.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Hepatitis C, Chronic Age 18 years or above, male or female Presence of HCV RNA (with or without anti-HCV) in serum at levels of at least 10,000 IU/ml. Willingness to undergo liver biopsy before or 6 hours after an initial injection of peginterferon. Written informed consent  Previous adequate treatment with any form of type I interferon (standard alpha interferon, peginterferon, beta interferon). Adequate treatment is considered at least 12 weeks of therapy. Other antiviral therapy within the last 6 months. If cirrhosis is present, decompensated liver disease, as marked by bilirubin greater than 4 mg percent, albumin less than 3.0 gm percent, prothrombin time greater than 2 sec prolonged, or history of bleeding esophageal varices, ascites or hepatic encephalopathy. Serum ALT or AST levels greater than 1000 micro/L (greater than 25 times ULN). Such patients will not be enrolled but may be followed until three consecutive determinations are below this level. Pregnancy or current breastfeeding. In women of child bearing potential or in spouses of such women, inability to practice adequate contraception, defined as vasectomy in men, tubal ligation in women, or use of condoms and spermicide, or birth control pills, or an intrauterine device until 6 months after the end of treatment with ribavirin given the potential for teratogenicity. Significant systemic or major illnesses including congestive heart failure, organ transplantation, serious psychiatric disease or depression, human immunodeficiency virus (HIV) infection, and angina pectoris. Pre-existing anemia (hematocrit less than 33 percent) or known history of hemolytic anemia. In patients in Groups C and D, liver biopsy will not be performed if hemoglobin levels fall to below 11 g/dl during ribavirin monotherapy. Epopoetin alfa or darbopoietin alfa therapy will be available to achieve an adequate hematocrit if clinically indicated for patients in all groups. Immunosuppressive therapy with either corticosteroids (more than 5 mg of prednisone daily on a chronic basis) or major immunosuppressive agents (such as azathioprine or 6-mercaptopurine). Patients receiving a short-course of corticosteroids for acute allergic reactions or asthma or chronic obstructive pulmonary disease exacerbations (less than 2 weeks of therapy) will be eligible for the study after 4 weeks off therapy. Evidence of another form of liver disease in addition to viral hepatitis (for example autoimmune liver disease, Wilson's disease, alcoholic liver disease, hemochromatosis, alpha 1 antitrypsin deficiency). Patients with concomitant non-alcoholic steatohepatitis but no other form of chronic liver disease will not be excluded from this study. Evidence of coronary artery disease or cerebral vascular disease, including abnormalities on exercise stress testing in patients with defined risk factors who will be screened for evidence of underlying coronary artery disease. Active substance abuse, such as alcohol, inhaled or injection drugs within the previous year. Evidence of hepatocellular carcinoma; either alpha-fetoprotein (AFP) levels greater than 200 ng/ml (normal less than 9 ng/ml) and/or ultrasound (or other imaging study) demonstrating a mass suggestive of liver cancer. Clinical gout. Active, serious autoimmune disease such as systemic lupus erythematosis, ulcerative colitis, Crohn s disease or rheumatoid arthritis that in the opinion of the investigators might be exacerbated by therapy with alpha interferon. These are considered the standard relative contraindications to peginterferon and ribavirin therapy