Hepatitis C virus infection and acute or chronic glomerulonephritis: an epidemiological and clinical appraisal.

Background: The relationship between hepatitis C virus (HCV) infection and acute or chronic glomerulonephritis (GN) is not well understood.

Methods: Two hundred and eighty-four patients with biopsy-proven GN and other renal diseases were studied in a multicentre survey performed during the period 1992-1995. Several clinical parameters were collected for each patient at the time of renal biopsy. We made a multivariate analysis by logistic regression model to evaluate the independent association of clinical and histological patient characteristics with HCV infection, as detected by anti-HCV antibody testing. In addition, three patients with HCV-related liver disease, membranous nephropathy, and proteinuria in the nephrotic range received therapy with interferon-alpha in standard doses.

Results: The prevalence of anti-HCV positivity was 13% (38/284). The frequency of anti-HCV positivity ranged between 0 and 100% in the different types of renal diseases, the difference was statistically significant (P = 0.0001). The anti-HCV rate was significantly higher in patients with cryoglobulinaemic membranoproliferative and mesangioproliferative GN than among the other individuals (14/14 (100%) vs 24/270 (9%), P = 0.0002). Our multivariate analysis by logistic regression model showed that age (P = 0.0017) and type of renal diseases (P = 0.0007) were independently and significantly associated with anti-HCV antibody. At the completion of treatment with interferon-alpha, 67% (2/3) of patients with membranous nephropathy had lowering of hepatic enzyme levels into the normal range whereas 100% (3/3) of these did not show significant reduction of proteinuria.

Conclusions: We observed strong association between HCV infection and cryoglobulinaemic GN. Age and type of renal disease were important independent predictors of anti-HCV positivity in our cohort of patients. Three anti-HCV-positive patients with membranous nephropathy did not show significant remission of nephrotic proteinuria after treatment with interferon-alpha. Our data do not appear to support an association between HCV and non-cryoglobulinaemic GN. Further epidemiological surveys, experimental studies and clinical trials are warranted to fully elucidate the role of HCV in non-cryoglobulinaemic GN.