The diagnostic value of citrullinated antigens with multiple citrulline similar motif in patients with rheumatoid arthritis

Background and aims

Anti-cyclic citrulline peptide (anti-CCP) antibodies are among the most critical biomarkers for the diagnosis of rheumatoid arthritis (RA), with citrullinated antigens being pivotal in triggering their production. This study aimed to explore the potential diagnostic value of multiple citrulline similar-motif antigen (MCSM) in RA.

Material and methods

A retrospective study was conducted on 135 patients with RA, 112 patients with other joint diseases (non-RA group), and 67 healthy controls from the Hangzhou Red Cross Hospital. The levels of MCSM in the peripheral blood were measured. The diagnostic value of MCSM in RA patients was assessed by receiver operating characteristic (ROC) curve analysis.

Results

MCSM in serum were significantly higher in RA patients than in non-RA patients (Signal-to-Cutoff ratio (S/CO): 3.2 vs 0.5, P < 0.0001) and healthy controls (S/CO: 3.2 vs 0.4, P < 0.0001). ROC analysis showed an area under the curve (AUC) of 0.932 for MCSM. Individually, MCSM outperformed anti-CCP and rheumatoid factor (RF), achieving sensitivity of 91.1 % and specificity of 95.5 %. Notably, MCSM detection rates were significantly higher in RA patients with pain duration under one year compared to anti-CCP (89.47 % vs. 52.65 %, P < 0.05).

Conclusion

MCSM demonstrate high sensitivity and specificity in diagnosing RA, with significant complementary value to anti-CCP and RF, and can increase the detection rate among RA patients with a disease duration of less than one year.