Renal manifestations of hepatitis C virus infection. Extrahepatic complications often are silent--and thus overlooked.

Renal involvement often occurs in HCV infection. The most common renal manifestation is MPGN with or without cryoglobulinemia. Patients with glomerulonephritis may have no clinical evidence of systemic or liver involvement. Pathogenesis of HCV-associated MPGN is mediated by glomerular deposition of circulating immune complexes containing HCV and anti-HCV. The treatment of choice for MPGN is IFN-alpha. However, success is limited, and many patients fail to respond or experience relapse on discontinuation of therapy. Newer treatment modalities, such as high-dose IFN-alpha and recombinant IFN alpha-2b and ribavirin combination therapy, have led to improved suppression of HCV RNA levels.