Cryoglobulinemia Vasculitis.

Cryoglobulinemic vasculitis (CryoVas) is a small-vessel vasculitis involving mainly the skin, the joints, the peripheral nervous system, and the kidneys. Type I CryoVas is single monoclonal immunoglobulins related to an underlying B-cell lymphoproliferative disorder. Type II and III cryoglobulins, often referred to as mixed cryoglobulinemia, consist of polyclonal immunoglobulin (Ig)G with or without monoclonal IgM with rheumatoid factor activity. Hepatitis C virus (HCV) infection represents the main cause of mixed CryoVas. The 10-year survival rates are 63%, 65%, and 87% in HCV-positive mixed CryoVas, HCV-negative mixed CryoVas, and type I CryoVas patients, respectively. In HCV-positive patients, baseline poor prognostic factors include the presence of severe liver fibrosis, and central nervous system, kidney, and heart involvement. Treatment with antivirals is associated with a good prognosis, whereas use of immunosuppressants (including corticosteroids) is associated with a poor outcome. In HCV-negative patients, pulmonary and gastrointestinal involvement, renal insufficiency, and age > 65 years are independently associated with death. Increased risk of lymphoma also should be underlined. Treatment of type I CryoVas is that of the hemopathy; specific treatment also includes plasma exchange, corticosteroids, rituximab, and ilomedine. In HCV-CryoVas with mild-to-moderate disease, an optimal antiviral treatment should be given. For HCV-CryoVas with severe vasculitis (ie, worsening of renal function, mononeuritis multiplex, extensive skin disease, intestinal ischemia…) control of disease with rituximab, with or without plasmapheresis, is required before initiation of antiviral therapy. Other immunosuppressants should be given only in case of refractory forms of CryoVas, frequently associated with underlying B-cell lymphoma.