Hepatitis C virus antibodies in systemic lupus erythematosus.

To determine the prevalence and significance of serum antibody to hepatitis C virus (HCV) in patients with systemic lupus erythematosus (SLE), we measured serum antibodies to HCV by enzyme-linked immunosorbent (ELISA) and by Abbott MATRIX Immunoblot assays in 42 patients with SLE, a condition associated with hypergammaglobulinemia. We used the polymerase chain reaction (PCR) to identify patients with HCV viremia. Five of 42 (11.9%) patients were seropositive for anti-HCV by ELISA; of these only two were positive by PCR; only one of three patients seropositive by Immunoblot assay was also positive by PCR. Both ELISA and the Immunoblot assays may be falsely positive for ongoing HCV infection in patients with SLE. Suspected HCV infection should be confirmed with PCR for serum HCV RNA in these patients.