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Diagnostic Value of Anti-Sa and Anticitrullinated Protein Antibodies in Rheumatoid Arthritis
The Journal of Rheumatology, 07/17/2012
Hou YF et al. – The results come from a newly developed electrochemiluminescent immunoassay (ECLIA) for detection of ACPA2 and the anti–Sa–antibody–based ELISA system. The combined application of ACPA2 and anti–Sa tests can improve the laboratory diagnosis of early rheumatoid arthritis (RA).
Methods- One hundred ninety–eight patients with early RA (< 1 yr duration), 112 with other rheumatic diseases, and 60 healthy individuals were studied.
- The combination of anti–Sa and ACPA2 positivity had the highest specificity (99.42%), but it had a rather low sensitivity (50.0%).
- The combination of anti–rheumatoid factor (RF) and ACPA2 showed the highest sensitivity (80.30%), with specificity of 95.93%.
- The mean titer of ACPA2 and RF was significantly higher in the anti–Sa–positive group compared to the negative group (ACPA2, p < 0.001; RF, p = 0.007).
- The 28–joint Disease Activity Scores of the anti–Sa–positive patients were significantly higher than those of the negative group (p = 0.01).
- The anti–Sa had no significant correlation with age, sex, antinuclear antibody, SSA, SSB, erythrocyte sedimentation rate, C–reactive protein, immunoglobulin A (IgA), IgG, IgM, C3, and C4.
