A systemic Vasculitis is found in 5 to 10% of HCV infected patients with mixed cryoglobulinemia (MC). It mainly involves the skin, peripheral nerve and the kidney and may be life threatening (15% of death). Twenty to 30% of HCV-MC Vasculitis patients are resistant to conventional therapy (i.e. antiviral therapy and/or immunosuppressors) and still have an active disease. An antiviral therapy with Peg-interféron is generally prescribed to control Vasculitis lesions and to slow down the hepatic fibrosis progression. Thus, new therapeutic approaches are necessary in such patients. We recently described a CD4+ CD25+ regulatory T cell (Treg) deficiency in HCV-related Vasculitis patients. Immunomodulatory effects of interleukin-2 (IL-2) are well established, notably the preferential expansion of Treg able to suppress inflammatory responses mediated by CD4+ and CD8+ T cells.