Frequency and significance of antibodies to hepatitis C virus in polyarteritis nodosa

We tested sera from 56 patients to determine the seroprevalence of antibodies to hepatitis C virus (HCV) in polyarteritis nodosa (PAN), to assess the specificity of these antibodies for hepatitis C virus encoded antigens, and to evaluate the clinical features in patients with HCV infection and PAN. Eleven (20%) were positive for anti-HCV by an enzyme immunoassay. Three (5%) had specific antibodies to HCV encoded antigens detected by recombinant immunoblot assay (RIBA II) and had HCV RNA detected by polymerase chain reaction. Patients with HCV infection were more likely to have liver and skin involvement and a diminished serum complement.