ANTIBODIES AGAINST CYCLIC CITRULLINATED PEPTIDE AND AGAINST MODIFIED CITRULLINATED VIMENTIN IN PATIENTS WITH PSORIATIC ARTHRITIS

Background: In association with the development of new aggressive treatment strategies in arthritic diseases, such as biologic therapy, there evolves a need for correct diagnosis as well as prediction of further development in the early stages of the disease. Rheumatoid factors (RF) are amongst the diagnostic criteria for RA, but they can occasionally be present in some PsA patients. They have no value for prediction of severity of PsA. Antibodies against cyclic citrullinated peptide (anti-CCP) are highly specific and sensitive for RA, even in early stages and until now they have the highest predictive value for erosions. Recent study have shown that presence of anti-CCP in patients with PsA was associated with polyarticular disease, but not with erosions [1]. Some of them may have had RA with coincidental psoriasis, or even overlap between RA and PsA, but most had true PsA.Antibodies against a modified citrullinated vimentin (anti-MCV) are members of the family of antibodies reactive with citrullinated proteins. Their presence in RA has similar predictive values as anti-CCP [2]. This antibody, to our knowledge has not been tested in PsA.Objectives: To find out the occurrence of anti-CCP and anti-MCV in a cohort of PsA patients.To try to establish the significance of these autoantibodies in diagnosis of PsA and possibly in prediction of further development of the disease.Methods: The diagnosis of PsA was determined using Moll and Wright criteria. In PsA patients who have been long-term followed, serum levels of anti-CCP and anti-MCV were examined. These were tested using ELISA methods: anti-CCP2 (Eurodiagnostika, Germany), anti-MCV (Orgentec, Germany).Results: Serum levels for both antibodies were available in 71 PsA patients. The presence of at least one of these antibodies was found in 12.6% of PsA patients. The positivity of anti-CCP was measured in 5.6%, the positivity of anti-MCV in 11.2%, simultaneous positivity of both antibodies in 4,2%, anti-CCP+/anti-MCV- in 1,4%, anti-CCP-/anti-MCV+ in 7% and the absence of both antibodies in 87.4% of patients. All anti-CCP positive and 7 out of 8 anti-MCV positive patients had erosions on X-ray.Conclusion: In the majority of our patients both antibodies were absent. Presence of anti-MCV was twice as much in comparison with anti-CCP. Anti-MCV antibodies were most frequently found in the absence of anti-CCP. In only one of the patients with the presence of at least one antibody, there was some doubt about the diagnosis of PsA with regard to the X-ray appearance, which was indicative rather of RA.Remarkable was the strong relationship of these autoantibodies to the presence of erosions, identifying the worse form of the disease in association with antibodies to citrullinated proteins. Because of a relatively small number of investigated patients the results must be considered preliminary. So far, we can conclude that the presence of anti-CCP2 and anti-MCV antibodies does not exclude the diagnosis of PsA and it could even be a predictor of severe disease course of PsA in those who are positive.Acknowledgement: Supported by project 0002372801 of the Czech Ministry of Health.References: 1. Alenius GM, Berglin E, Rantapaa Dahlqvist S. Antibodies against cyclic citrullinated peptide (CCP) in psoriatic patients with or without joint inflammation. Ann Rheum Dis. 2006 Mar;65(3):398-400. Epub 2005 Aug 11.2. Dejaco C, Klotz W, Larcher H, Duftner C, Schirmer M, Herold M. Diagnostic value of antibodies against a modified citrullinated vimentin in rheumatoid arthritis. Arthritis Res Ther. 2006;8(4):R119.Citation: Ann Rheum Dis, volume 66, supplement II, year 2007, page 420Session: Psoriatic arthritis