The association between hepatitis B virus and membranous glomerulonephritis and membranoproliferative glomerulonephritis (MPGN) was first described in 1971. Recently, a similar association between hepatitis C virus (HCV) and glomerulonephritis (GN) has been reported. We investigated the prevalence of hepatitis C serum antibodies (anti-HCV) in patients with primary GN followed up at our Nephrology Outpatient Clinic between March 1993 and November 1995. The diagnosis of primary GN was established after excluding the presence of connective tissue disease, diabetes, infectious disease, and malignancy. Anti-HCV antibodies were detected by a second-generation enzyme immunosorbent assay and HCV RNA by polymerase chain reaction. Of 81 patients with primary GN, 24 had membranous glomerulonephritis, 17 MPGN, 15 minimal-change disease, 12 focal-segmental glomerulosclerosis, 9 diffuse proliferative GN, and 4 IgA nephropathy. Anti-HCV were detected in 2 cases (2.5%), both were HCV RNA positive and had a polyclonal mixed cryoglobulinemia (IgM-IgG). These 2 cases both came from the group of 17 patients with MPGN. Biochemical investigation in these patients revealed persistent elevation of serum aminotransferase activity, and a liver biopsy specimen in 1 of them showed evidence of chronic active hepatitis. We conclude that in our setting the prevalence of anti-HCV among patients with primary GN is low, being higher (11.8%) only if we consider the patients with MPGN as the reference group. Further studies are necessary to clarify this association and to determine appropriate therapy for these patients.

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