Cryoglobulinemia are responsible for systemic vasculitis, and the most frequently targeted organs are the skin, joints, kidney and peripheral nervous system. Cryoglobulinemia vasculitides are associated with significant morbidity and mortality, and require therapeutic intervention. With the discovery of hepatitis C virus (HCV) as the etiologic agent for most cases of mixed cryoglobulinemia new opportunities and problems for crafting therapy of HCV mixed cryoglobulinemia (MC) have emerged. A new and major concern was the potential adverse effects that immunosuppressive therapy with glucocorticoids and cytotoxic drugs could have on an underlying chronic viral infection. Alternatively the discovery of HCV provided the opportunity to control HCV-MC with antiviral therapy based on the belief that the underlying infection was driving immune complex formation and resultant vasculitis. Inducing a sustained virologic and clinical response and minimizing the use of immunosuppressive drugs are the main goals in the treatment of patients with HCV-MC vasculitis. Aggressive antiviral therapy has been shown to induce a complete remission of HCV-MC in up to 70% of patients. New antiviral combination, Interferon (IFN)-free regimens have recently proved very high virological response rate and with a very good safety profile and now need to be evaluated in severe and/or refractory HCV-MC patient's population.

Inclusion Criteria:

• at least 18 years of age or older
• present an active HCV vasculitis defined by a clinically active vasculitis with skin, joint, renal, peripheral nerve, central neurological, digestive, pulmonary and/or cardiac involvement (no histological evidence needed if patient had purpura)
• chronic active HCV infection (positive HCV RNA)
• informed consent

Exclusion Criteria:

• non-active cryoglobulinaemia vasculitis
• HIV
• active hepatitis B virus (HBV) infection
• current decompensated cirrhosis.

To be eligible, the patient must have been at least 18 years of age or older, without any upper age limit, informed and present an active HCV vasculitis defined by a clinically active vasculitis with skin, joint, renal, peripheral nerve, central neurological, digestive, pulmonary and/or cardiac involvement (no histological evidence needed if patient had purpura), and a chronic active HCV infection (positive HCV RNA).