ANTI-CYCLIC CITRULLINATED PEPTIDE ANTIBODIES: BEYOND RHEUMATOID ARTHRITIS

Background: The determination of anti-cyclic citrullinated peptide antibodies has diagnostic and prognostic value in rheumatoid arthritis, with a sensitivity similar to that of the rheumatoid factor and of greater specificity. Nonetheless, their presence has been described in other diseases and in healthy people. Objectives: To describe the clinical characteristics of a cohort of patients with positive anti-cyclic citrullinated peptide antibodies. Methods: The retrospective study was done at the university hospital with a reference population of 700,000 between 2007 and 2009. We reviewed the medical records of patients with anti-cyclic citrullinated peptide antibodies (citrullinated vimentin peptides) greater than or equal to 20 U/ml excluding those cases without clinical information. Technique used: ELISA anti-CMV (Orgentec, Freiburg, Germany). Results: We carried out 1222 determinations, of which 418 (34%) were positive. We analyzed 320 patients: 103 men (32%) and 217 women (68%). In 234 cases (73%) patients had an associated rheumatic disease (Table 1). 64.5% of patients with rheumatoid arthritis, who had values above 100 U/ml, where seropositive and erosive forms. In the cases of vasculitis and connective tissue disease the values were between 20 and 50 U/ml. They were above 50 U/ml only in six patients: 3 with SLE and 3 with Sjögren syndrome. The distribution in Still's disease, palindromic rheumatism and elderly-onset arthritis was similar for all values. 72% of the non-filiated arthritis had values between 20 and 50 U/ml. In the miscellaneous group (psoriatic arthritis, microcrystalline arthritis, polymyalgia rheumatica, sarcoidosis, arthritis associated with inflammatory bowel disease and postinfectious arthritis), 75% had values less than 50 U/ml. The value of 100 U/ml was only exceeded in a case of polymyalgia rheumatica and a case of chondrocalcinosis. In 86 cases (27%) the patients did not have any associated rheumatic disease (Table 2). Fifteen patients (17%), two of whom were smokers, had values above 50 U/ml. In six cases the values were greater than 100: 2 with nephropathy, 2 with lung disease (pulmonary hypertension and idiopathic pulmonary fibrosis), 1 with autoimmune hemolytic anemia and 1 case of drepanocytosis. Table 1 20-50 U/ml51-100 U/ml101-500 U/ml>500 U/mlTotal Rheumatoid arthritis21193651127 Elderly-onset arthritis535215 Non-filiated arthritis1842125 Connective and vasculitis3022236 Still's disease12104 Palindromic rheumatism13127 Miscellaneous1531120 Table 2 20-50 U/ml51-100 U/ml101-500 U/ml>500 U/mlTotal Endocrinology and nephropathy1622020 Lung disease902011 Hematology and infections1842024 Miscellaneous2830031 Conclusion: Although anti-cyclic citrullinated peptide antibodies are highly specific for rheumatoid arthritis, they have also been described in other rheumatic diseases. Values above 100 U/ml usually relate to rheumatoid arthritis. Values between 20-50 U/ml without articular simptoms, must be considered negative, so this determination must be valued only in the context of rheumatic disease. Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 69, supplement 3, year 2010, page 361Session: Rheumatoid Arthritis – prognosis, predictors and outcome (Poster Presentations )