Hepatitis C and glomerulonephritis

Summary: Several systemic viral infections have been associated with the development of glomerular lesions. of the viruses that cause liver disease hepatitis B was the first to be recognized. the recent availability of serologic tests for the hepatitis C virus (HCV) has uncovered an association between HCV infection and renal disease. the principal glomerular lesion that develops is that of a membranoproliferative glomerulonephritis (MPGN), usually in association with antigenaemia and circulating immune complexes that have the characteristics of mixed cryoglobulinaemia represented by polyclonal IgG and monoclonal IgM with rheumatoid factor activity. the presence of a very high percentage of anti-HCV seropositivity in cryoglobulinaemic forms of MPGN suggests that the virus plays an important role in the pathogenesis of the associated immune complex glomerulonephritis. Precipitates containing HCV-RNA and circulating anti-HCV IgG and IgM have been found in the majority of such cases. the course of the renal disease that develops is progressive. Treatment with interferon alpha appears to attenuate the progression of the renal lesions, and the response to treatment appears to be closely related to the clearance of hepatitis C viraemia. Renal lesions also occur in the absence of clinical evidence of liver disease or mixed cryoglobulinaemia. In addition to MPGN, membranous glomerulonephropathy, IgA nephropathy and focal segmental glomerulosclerosis have been reported in these cases of HCV infection. the prevalence of glomerular lesions in patients with HCV infection remains to be determined. the available serologic tests for HCV are still in evolution. In the meantime, all patients presenting with glomerular disease should be screened for HCV.