Absence of antibodies to cyclic citrullinated peptide in sera of patients with hepatitis C virus infection and cryoglobulinemia

TLDR

Measurement of anti‑CCP may aid in diagnosing rheumatoid arthritis in patients with chronic hepatitis C infection. The study aimed to determine whether anti‑CCP antibodies are present in chronic HCV infection. Anti‑CCP and rheumatoid factor were measured by second‑generation ELISA in sera from 50 HCV patients without cryoglobulinemia, 29 with mixed cryoglobulinemia, and 20 healthy donors. No anti‑CCP antibodies were detected in uncomplicated HCV patients, while borderline‑positive results occurred infrequently in mixed cryoglobulinemia patients due to nonspecific ELISA binding, and rheumatoid factor was frequently elevated in both HCV groups.

Abstract

To determine if antibodies to cyclic citrullinated peptide (anti-CCP) are found in chronic hepatitis C virus (HCV) infection.Rheumatoid factor (RF) and anti-CCP were measured in sera from 50 patients with HCV infection but without cryoglobulinemia, sera from 29 patients with mixed cryoglobulinemia (including 13 with rheumatic symptoms and 5 with arthritis), and sera from 20 normal blood donors. Anti-CCP was measured by second-generation enzyme-linked immunosorbent assay (ELISA).No sera with elevated anti-CCP were found in patients with HCV infection without cryoglobulinemia, and in that population, the maximum anti-CCP was 10 units, well below the positive cutoff of 20 units. Positive findings on RF testing >13 IU/ml were present in 22 (44%) of the HCV patients, with RF >50 IU/ml in 8 (16%) and a maximum RF of 526 IU/ml. Of the cryoglobulinemia patients, 22 (76%) had positive results on tests for RF, including 18 (62%) with RF >50 IU/ml and a maximum RF of 5,540 IU/ml. Two (6.9%) of the cryoglobulinemia patients had borderline-positive findings on tests for anti-CCP (25 units and 37 units), which were false-positive results caused by nonspecific binding in the ELISA. No association between the RF and the anti-CCP concentrations was found.Whereas RF was frequent in patients with HCV infection with and without cryoglobulinemia, anti-CCP was not observed in patients with uncomplicated HCV infection. Borderline-positive anti-CCP results were observed infrequently in patients with mixed cryoglobulinemia and were caused by nonspecific binding to plastic. Measurement of anti-CCP may help in diagnosing RA in patients with chronic HCV infection.