Hepatitis C virus infection and renal disease after renal transplantation.

Hepatitis C virus (HCV) infection is the main cause of chronic liver disease after renal transplantation (RT). It is considered in some series to be a risk factor for graft loss and patient death. Also, HCV has been implicated in the pathogenesis of glomerular diseases in native and transplanted kidneys. The presence of membranoproliferative (MP) or membranous (M) glomerulonephritis (GN) in HCV-positive patients has been well documented after RT, but there is no clear data concerning the real prevalence of HCV-induced glomerulonephritis. MPGN with or without cryoglobulinemia and MGN have been described in HCV RNA-positive patients in general without severe liver disease. Also, there is a possible association between HCV infection and acute/chronic transplant glomerulopathy. Renal thrombotic microangiopathy has been described in HCV-positive patients with positive anti-cardolipin antibodies. The pathogenesis of MPGN and MGN in HCV patients after RT seems to be similar to that which occurs in native kidneys: the deposition of immune complexes containing HCV proteins in the glomeruli. Renal biopsy, using light microscopy, immunofluorescence techniques, and electron microscopy, is useful to achieve a correct diagnosis. Unfortunately, interferon is not recommended due to the significant risk of rejection. The possibility of pegylated interferon needs to be tested. Ribavirin can improve proteinuria but HCV RNA remains positive. Finally, recent data suggest that the use of interferon in HCV patients on dialysis can negate HCV RNA and prevent associated glomerulonephritis after RT.