Anti-cyclic citrullinated peptide antibodies and joint involvement in Behçet's disease

We aimed to determine the prevalence of anti-cyclic citrullinated peptide (anti-CCP) antibodies in a large group of Korean patients with Behçet's disease (BD), with and without joint involvement, and to compare these findings with the prevalences of anti-CCP antibodies in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We tested 189 patients with BD, 105 with RA, and 36 with SLE for anti-CCP antibodies and IgM rheumatoid factor in serum. We reviewed the medical records of patients with BD to investigate their personal and clinical characteristics as well as their laboratory test results. Anti-CCP antibodies were detected in seven of the 189 BD patients (3.7%), at a mean titer of 30.6±44.4 U/mL, in 86 of the 105 RA patients (81.9%) with a mean titer of 198.8±205.7 U/mL, and in nine of the 36 SLE patients (25%) with a mean titer of 180.4±113.9 U/mL. One of the seven anti-CCP-positive BD patients fulfilled the diagnostic criteria for both BD and RA. Five of the seven anti-CCP-positive BD patients (71.4%) had polyarticular joint involvement, and the other two patients (28.6%) had oligoarticular involvement. We determined the prevalence of anti-CCP antibodies in a large group of Korean BD patients with and without joint involvement. Negative anti-CCP test in patients with BD may help to differentiate BD from RA and SLE, all of which present with similar clinical features.