Anti-citrullinated alpha-enolase peptide 1 antibody in the diagnosis of rheumatoid arthritis

Abstract

Objective To detect the anti-citrullinated alpha-enolase peptide 1(CEP-1) antibody in rheumatoid arthritis(RA). Methods One hundred and twenty-nine patients with RA were enrolled randomly. Thirty-one patients with primary Sjogren's syndrome (pSS), 32 patients with systemic lupus erythematosus (SLE), 32 patients with osteoarthritis (OA), and 106 healthy controls (HC) were include into this study. Anti-CEP-1 antibody was detected by enzyme-linked immunosorbent assay (ELISA). The correlations between serum anti-CEP-1 antibody and clinical features, disease activities, laboratory tests or Sharp scores of RA patients were evaluated. Mann-Whitney U test and χ2 test were used for statistical analysis. Results ①Anti-CEP-1 antibodies were positive in 64.3%(83/129) of RA patients, 22.6%(7/32) of pSS patients, 12.5%(4/32) of SLE patients, none of OA patients (0/32) or healthy controls. The positivity of anti-CEP-1 antibody was significantly higher than those in pSS (χ2=17.7), SLE (χ2=25.7), OA (χ2=42.5), and healthy controls (χ2=102.6) (P<0.01, respectively). The specificity of anti-CEP-1 antibody in RA was 94.5%. ② In patients without anti-citrullinated protein/peptide autoantibodies (ACPA), rheumatoid factor (RF) or the patients without ACPA and RF, the positive rate of anti-CEP-1 antibody was 30.3%(10/33), 41.9%(18/43) and 22.7%(5/22), respectively. ③ Compared with patients without anti-CEP-1 antibodies, patients with anti-CEP-1 anti-bodies had higher rates of joint deformity, bone erosion and high disease activities (P<0.05, respectively). ④ Higher rate of interstitial lung disease (ILD) was found in RA patients with anti-CEP-1 antibody (19.3% vs 4.3%, χ2=5.494, P<0.05). ⑤ The patients with anti-CEP-1 anti-body had higher rates of elevated erythrocyte sedimentation rate (ESR) (χ2=6.543) and decreased serum albumin (χ2=6.59), compared to patients without anti-CEP-1 antibody (P<0.05, respectively). Conclusion Anti-CEP-1 antibody has high sensitivity and specificity for RA diagnosis. Combination of anti-CEP-1 antibody with other RA antibodies might improve the early diagnosis of RA. Anti-CEP-1 antibody is significantly associated with joint damage, disease activity and pulmonary interstitial fibrosis. Key words: Arthritis, rheumatoid; Diagnosis; Anti-CEP-1 antibody