High positivity of anti-CCP antibodies in patients with Down syndrome.

The aim of the present study was to evaluate the prevalence of anti-cyclic citrullinated peptide (CCP) antibodies in patients with Down's syndrome (DS) previously tested for IgM rheumatoid factor (RF) and to correlate the results with clinical findings. Eighty-eight patients with DS previously tested for IgM-RF were divided into two groups matched for sex and age. Group A consists of 42 RF positive patients and group B of 44 RF negative patients. The presence of anti-CCP antibody was determined using a second-generation enzyme-linked immunosorbent assay. A total of 52.3% (45/86) of DS patients were positive for anti-CCP antibodies. Twenty-four patients (57.1%) of the RF positive group and 21 (47.7%) of the RF negative group presented anti-CCP circulating antibodies. The concordance between both tests was 54.6%. None of the patients had clinical evidence of rheumatoid arthritis or juvenile idiopathic arthritis. Although a high prevalence of anti-CCP antibodies was observed in DS patients, no association has been found presently with clinical disease. Careful follow-up of these patients will be necessary to clarify the real significance of these findings.