Kidney disease in patients with chronic hepatitis C.

There is an increasing recognition of the association between chronic hepatitis C virus infection and glomerular diseases. Renal complications may be the presenting manifestation of hepatitis C virus infection. Patients may present with signs and symptoms of cryoglobulinemic systemic vasculitis, proteinuria, microscopic hematuria, acute renal failure, or nephrotic syndrome. The pathogenesis of hepatitis C virus associated with renal disease remains incompletely understood; however, deposition of circulating immune complexes in the subendothelial space and mesangium in the glomeruli seems to play a major role. The most common renal pathology associated with hepatitis C virus infection is type I membranoproliferative glomerulonephritis with or without cryoglobulinemia. In patents who do not have significant renal impairment, combination therapy with interferon alfa (IFN-alpha) and ribavirin seems to be the treatment of choice, although the experience with this combination is quite limited in patients with renal involvement. A prolonged course of high-dose IFN-alpha has been most commonly used for these patients with significant success, but relapse of hepatitis C viremia and renal disease after discontinuation of therapy have frequently occurred.