Background Antibodies against citrullinated peptides have gained special importance in the diagnosis of rheumatoid arthritis (RA) (1,2).
Objectives This study aims to investigate the diagnostic sensitivity and specificity of anti-mutated citrullinated vimentin (anti-MCV) antibodies for rheumatoid arthritis (RA) in comparison to IgM RF and anti-CCP and to assess their clinical significance particularly as a marker of RA activity.
Methods 60 patients with different rheumatic diseases 40 patients with RA and 20 patients with other rheumatic diseases (disease controls) were recruited from Ain Shams University Hospitals, and 20 persons (healthy controls) All participants underwent history taking, clinical examination, laboratory and radiological investigations, and calculation of disease activity score DAS-28 for each RA patient. Enzyme-linked immunosorbent assay (ELISA) techniques were used to detect RF-IgM, anti-CCP antibodies, and anti-MCV antibodies
Results The sensitivity of anti-MCV antibodies was 95% with 97.1% specificity. For anti-CCP antibodies the sensitivity was 95% and the specificity was 100%. The sensitivity of RF was 72.5% with 97.1% specificity. Anti-CCP antibodies have higher diagnostic specificity and positive predictive value than RF and anti-MCV antibodies. The best cut-off value for the anti-MCV test was found at 22.7 U/L, while that for Anti-CCP antibodies and RF were 20 u/l and 44 IU/ml respectively. Of RA patients with positive RF, 86.2% were anti-MCV antibodies positive, including only 6.8% with negative Anti-CCP. Of patients with negative RF, 81.8% were positive for anti-MCV, including 9% who tested negative for anti-CCP.
Conclusions Our results suggest that anti-MCV antibodies may be valuable for diagnosing RA and that, it may be better to assay both anti-MCV and anti-CCP in RF -negative RA patients without replacing them. Long-term study is required to find out whether anti-MCV antibodies can be used as predictive test for incidence of RA.
Klareskog L, Rönnelid J, Lundberg K, Padyukov L, Alfredsson L: Immunity to citrullinated proteins in rheumatoid arthritis. Annu Rev Immunol 2008, 26: 651-675.
Shmerling RH, Delbanco TL: How useful is the rheumatoid factor? An analysis of sensitivity, specificity and predictive value. Arch Intern Med. 1992,152: 2417–2420.
Disclosure of Interest None declared