Vaccination and Autoimmunity

Chronic infection with the hepatitis C virus (HCV) is among the most common aetiologic factors influencing vasculitis in humans. Long-term infection is associated with small-vessel vasculitis (HCV-associated cryoglobulinemic vasculitis [CV]) in less than 5% of cases, and it is associated more rarely with medium-size vasculitis (polyarteritis nodosa-like). In recent years, significant advances have been made in our understanding of the pathogenesis of HCV-associated CV and its long-term prognosis. Furthermore, new immunosuppressive agents such as rituximab (a B cell-depleting agent) have been shown to be efficacious with limited toxicity, providing a promising alternative to current immunosuppressives for the treatment of HCV-associated CV. This chapter presents the pathogenesis, clinical features and recent therapeutic options for HCV-associated CV and medium-size vasculitis.