Infection and Autoimmunity, 3rd Edition - Chapter 18: Vasculitides and Hepatitis C Infection

Chronic infection due to hepatitis C virus (HCV) is among the most common etiologic factors of vasculitis in humans. Long-term infection is associated in less than 5% of cases with an immune-complex-mediated small-vessel vasculitis (cryoglobulinemic vasculitis – CV) or more rarely with a medium-sized vasculitis (polyarteritis nodosa-like). In recent years, significant advances have been made in our understanding of the pathogenesis, long-term prognosis, and more importantly treatment of HCV-associated CV. The newer oral direct-acting antivirals (DAAs) achieve HCV clearance in more than 95% of HCV patients (with or without cryoglobulinemia) and have transformed our therapeutic approach in patients with HCV-associated CV. Currently, all patients with CV should be treated with DAAs. Glucocorticoids, immuno-modulating or immunosuppressive agents (such as the B-cell-depleting agent rituximab), and/or plasmapheresis is added to DAAs in patients with severe or life-threatening disease manifestations. With this approach, ∼85% of patients achieve initially complete or partial clinical remission. Nevertheless, less than half of the patients show clear cryoglobulins and ∼15% demonstrate clinical relapses during long-term follow-up, despite viral clearance, indicating the need for optimization of our therapeutic approach. In this chapter, the pathogenesis, clinical features, and recent therapeutic options in HCV-associated CV and medium-sized vasculitis are presented.