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 membrano-proliferative 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.