In all patients the presence of anti-HCV antibodies will be assayed by a third-generation immunoenzymatic test (Ortho Diagnostic Systems, Raritan, NJ) and by confirmatory test (recombinant immunoblotting assay, Chiron Corp., Emeryville, CA). A standardized genotyping assay (Inno-Lipa HCV III, Innogenetics, Gent, Belgium) will be used.