To determine whether anti-cyclic citrullinated peptide (anti-CCP) antibodies, which are a highly specific test for rheumatoid arthritis (RA), could differentiate between hepatitis B virus (HBV)-associated arthropathy and concomitant RA in Korean patients with chronic HBV infection.
We investigated 240 patients with HBV infection. Anti-CCP antibodies were measured by ELISA and rheumatoid factor (RF) by the latex fixation test. Patient records were reviewed, and a standard form was used to record all demographic, clinical, and laboratory characteristics. Patients were divided into 4 groups according to joint symptoms: asymptomatic, arthralgia, oligoarthritis, and RA. We categorized liver disease into 3 groups: carrier, chronic hepatitis, and cirrhosis.
Anti-CCP antibodies and RF were detected in 11 and 28 of 240 patients, respectively. Anti-CCP antibodies were detected in 9 of 10 RA (90%) and 2 of 230 non-RA patients (0.86%). The positive rate for RF was 90% in RA and 8.3% in non-RA. Eight of 10 RA patients were positive for both RF and anti-CCP antibodies. RF was detected in 11 patients without joint symptoms, 4 with arthralgia, and 4 with oligoarthritis, whereas anti-CCP antibodies were found in 1 patient without joint symptoms and 1 with oligoarthritis. Specificity of anti-CCP antibody for RA was 99.1%, whereas RF showed 91.7% specificity (p<0.0002). We compared the titers and positive detection rates of anti-CCP antibodies and RF among liver disease subgroups. There was no significant between-subgroup difference.
Measurement of anti-CCP antibodies is better than RF detection to discriminate HBV-associated arthropathy from concomitant RA in patients with chronic HBV infection.