Objective: To investigate the prevalence and the diagnostic values of antibodies to the citrullinated HPVP in early-stage rheumatoid arthritis.
Methods: Antibodies against HPVP and citrullinated HPVP were detected by ELISA in the sera of 101 patients with early-stage RA, 149 patients with other rheumatic diseases and 40 healthy controls. The prevalence and diagnostic values of these antibodies for early-stage RA were analyzed by statistical software.
Results: (1)The prevalence of IgG, IgM antibodies to citrullinated HPVP in early-stage RA were significantly higher than that in the patients with other rheumatic diseases as well as in the healthy individuals.(2)The diagnostic sensitivity of IgG and IgM citrullinated HPVP antibodies in early-stage RA were 62.4% and 66.3% respectively and the specificity value of the two antibody isotypes were 88.7% and 89.6%,similar to that of the anti-CCP antibody. (3)The positivity rates of IgG and IgM antibodies against citrullinated HPVP were 59.4% and 71.9% in IgM-RF negative early-stage RA patients, and 39.4% and 51.5% in anti-CCP antibody negative early-stage RA patients. (4) The DAS28 score [ IgG (6.3±1.0) vs. (5.6±0.9), P=0.002; IgM (6.2±1.1) vs. (5.6±0.8), P=0.008] , X-ray stages (IgG 56.1% vs. 21.2%, P=0.001;IgM 50.9% vs. 29.4%, P=0.036),anti-CCP antibodies(IgG 96.8% vs. 55.3%, P=0.001; IgM 89.6% vs. 64.7%, P=0.023) in citrullinated HPVPP positive patients were higher than those of citrullinated HPVP negative patients. Additionally, the levels of ESR[IgG(70.3±32.4)vs.(51.9±27.8), P=0.004; IgM (67.4±31.5)vs.(53.8±27.7), P=0.035] in citrullinated HPVP positive patients were higher than those of negative patients (P<0.05).
Conclusion: IgG and IgM antibodies to citrullinated HPVP are highly sensitive and specific novel biomarkers for early-stage RA diagnosis, and are related to disease activity and joint damage.