Treatment of hepatitis C cryoglobulinemia: mission and challenges.

Mixed cryoglobulinemia (MC) is a syndrome resulting from cold-insoluble immunoglobulin complexes or cryoglobulins (CGs) that precipitate in the serum of 40% to 50% of patients with chronic hepatitis C virus (HCV) infection. The pathogenesis of cryoglobulinemia likely occurs due to chronic viremia and generation of rheumatoid factor following continuous presentation of antigen-immunoglobulin complexes to B cells. CGs are thought to be responsible for a variety of extrahepatic manifestations associated with HCV, including vasculitis, glomerulonephritis, arthritis, and neuropathies, which occur in approximately 10% of HCV patients with CGs. CGs also are a powerful predictive factor for progressive liver disease and the aggressive reoccurrence of liver disease in HCV-positive patients after liver transplantation. First-line therapy for MC due to HCV infection is antiviral therapy with pegylated interferon-alpha and ribavirin. Viral eradication usually produces marked reduction of physical complications and arrests end organ damage concomitant with clearance of CG. Additional prospective, controlled studies are necessary to determine whether CG influences patient virologic response and/or its durability to antiviral therapy. Immunomodulators such as corticosteroids and cyclophosphamide are efficacious for palliative treatment of the symptomatology of HCV cryoglobulinemia but may enhance viral replication. Consequently, prolonged therapy with immunomodulatory agents should be limited to severe vasculitis or aggressive glomerulonephritis in patients with MC due to HCV who have failed to respond to antiviral therapy. In acute, fulminant presentations, plasmapheresis may provide temporary relief and arrest the rapid progression of the disease so that additional therapy can be initiated.