Antibodies against cyclic citrullinated peptide in Japanese psoriatic arthritis patients.

Anti-cyclic citrullinated peptide antibodies (anti-CCP) are highly considered to indicate disease severity and be predictive markers in rheumatoid arthritis (RA). RA patients who are positive for anti-CCP tend to progress more frequently to joint deformity and functionally deteriorate more than negative patients. A study concerning the presence of anti-CCP in Japanese patients with psoriatic arthritis (PsA) has been published. Our aim was to clarify that anti-CCP could be a potentially useful marker in PsA patients. We herein describe a PsA patient with presence of anti-CCP. We examined anti-CCP in 15 patients with PsA, and compared with 18 controls who had other types of psoriasis. Three PsA patients were positive for anti-CCP, but no controls showed positive. The anti-CCP-positive patients had higher counts of radiographic erosion, higher prevalence rates of polyarticular disease, use of disease-modifying anti-rheumatic drugs, and the human leukocyte antigen DRB1*04 shared epitope than negative patients. Our study demonstrated that anti-CCP was potentially both predictive and a severity marker of joint involvement in PsA, the same as in RA.