Viral hepatitis C is treated with peg-interferon alpha 2a/2b and ribavirin for 24 Weeks. In many patients, there is no efficacy of this treatment on hepatitis C, and there is no treatment recommended for them. Interferon gamma has anti-infectious and anti-fibrosis activity. This study will evaluate the effect, after a second treatment with peg-interferon alpha 2a and ribavirin for 12 Weeks, of the addition of interferon gamma in non responders patients. 65 patients will be included in order to include 27 patients who are non responders after 12 weeks of a second treatment and are eligible to receive interferon gamma. Patients will then receive peg-interferon alpha 2a (180 micro g once a week, by injection), ribavirin (1,000 to 1,200 mg per day, according to weight) and interferon gamma (100 micro g thrice a week, by injection) during 8 months