Hepatitis C virus-induced vasculitis: therapeutic options.

Hepatitis C virus (HCV) is now well recognised as the main etiologic agent of mixed cryoglobulinaemia vasculitis (cryovas). New opportunities and problems in developing therapy have therefore emerged. Antiviral therapy with pegylated interferon-α and ribavirin (plus protease inhibitor in the case of HCV genotype 1 infection) should be considered as induction therapy for HCV-cryovas with mild to moderate disease severity and activity. An early virologic response to antiviral therapy is correlated with a complete clinical response of HCV-cryovas. In patients presenting with more severe disease (ie, worsening of renal function, mononeuritis multiplex, extensive skin disease including ulcers and distal necrosis), an immunosuppression induction phase is often necessary while awaiting the generally slow response to antiviral treatments. Combination therapy with rituximab plus an optimal antiviral agent is recommended, as it may target the downstream B cell arm of autoimmunity and the viral trigger. Careful monitoring for adverse effects is mandatory, since some manifestations of HCV-cryovas, such as peripheral neuropathy or skin ulcers, may worsen with interferon-based therapy. Clinicians should be aware of the possibility of malignant lymphoma when patients develop a relapse of cryovas without virological relapse. Room for other treatment strategies is very limited. Low-dose corticosteroids may help to control minor intermittent inflammatory signs such arthralgia but do not succeed in case of major organ involvement. Other immunosuppressants should be given only in case of refractory forms of HCV-cryovas, which are frequently associated with an underlying B cell lymphoma.