Anti-MCV antibodies are associated with more severe rheumatoid arthritis, measured by DAS28, ESR, and swollen joint count, compared with anti-CCP2, CCP3, and CCP3.1 antibodies
Detection of antibodies against citrullinated proteins or peptides (ACPA) has become a valuable tool in the diagnosis of rheumatoid arthritis (RA) and in predicting clinical outcome.
Antibodies to synthetic cyclic citrullinated peptides (anti-CCP) were the first markers for serologic detection of RA aside from rheumatoid factor.
The test for antibodies against the native protein citrullinated vimentin has been a further advancement towards enhanced sensitivity and extended prognostic value.
The occurrence of vimentin in synovial cells in RA, and the recent observation, that vimentin is secreted and modified by macrophages depending on proinflammatory signals makes this protein a suitable prognostic marker for the disease.
A recently published study by L Innala, S Rantapaa Dahlqvist and their co-workers compares the predictive values of different generations of anti-CCP tests (CCP2, CCP3, CCP3.1) by various manufactures to the MCV-Elisa by Orgentec Diagnostika.
They determined ACPA-titers in 210 patients with early RA and in 102 healthy controls and compared the test results to clinical parameters of disease activity, eg, swollen and tender joints, CRP, ESR, radiological progression at baseline, at 6,12 and 24 months.
During these 24 months the patients received basic treatment with DMARDs, partially in combination with prednisolone, or a TNF-alpha blocker.
Patients with radiological progression at 24 months already had at baseline higher concentrations of anti-MCV, anti-CCP3 and anti-CCP3.1 antibodies.
Positive test for ACPA or rheumatoid factor and ESR at baseline predicted radiological progression at 24 months.
Radiologic progression was predicted equally and the accuracy as a diagnostic marker was similar for anti-MCV and the other ACPAs.
Patients with MCV antibodies had significantly less reduction in DAS 28 over time than patients without.
A significant decrease in the anti-MCV-titers corresponded to a therapeutic response.
In none of the other ACPAs a significant difference could be observed, irrespective of therapeutic response.
The authors conclude that MCV antibodies are associated with a more aggressive disease.
Moreover, anti-MCV is the best antibody test to identify persistent inflammatory activity, measured by DAS28, ESR, CRP and swollen joint count, compared with CCP2-, CCP3- and CCP3.1-antibodies.
