Usefulness of anti-CCP antibodies in patients with hepatitis C virus infection with or without arthritis, rheumatoid factor, or cryoglobulinemia

Abstract

The presence of antibodies to cyclic citrullinated peptide (CCP) has high specificity in the diagnosis of rheumatoid arthritis (RA). Hepatitis C virus (HCV) infection may induce extra-hepatic manifestations, such as polyarthritis that mimic RA. The aim of this study was to determine the prevalence of anti-CCP antibodies in HCV-infected patients with or without arthritis, rheumatoid factor (RF), or cryoglobulinemia and to investigate whether anti-CCP antibodies may be helpful in discriminating patients with RA from patients with HCV-associated arthropathy. A total of 44 patients with RA, 34 patients with HCV infections, and 42 control patients with non-RA rheumatic diseases were recruited for the study. Anti-CCP antibody levels were determined by enzyme-linked immunosorbent assay. We found that, consistent with other reports, patients with RA were more likely to have high titers of anti-CCP antibody than HCV-infected or control patients. A significant number of HCV-infected patients with neither RF nor cryoglobulinemia were also positive for anti-CCP antibodies (the three positive values were 36.10, 8.65, and 5.83 U/ml, P < 0.01 compared with the control patients). The presence of cryoglobulinemia and/or RF in HCV-infected patients did not affect the anti-CCP outcomes. Although anti-CCP antibodies remain to be a very useful tool in discriminating RA from non-RA, HCV-infected patients with neither RF nor cryoglobulinemia may have anti-CCP antibodies. Because of limited patient numbers, this tentative conclusion may need further confirmation with inclusion of more patient population.