Assessment of Serum and Salivary Vimentin Levels in Rheumatoid Arthritis Patients

Aim: This work aimed to determine the serum and salivary level of vimentin in patient with RA. Materials and Methods: A total of 84 participants with RA (69) and controls (15) were submitted in this work. Serum and Salivary vimentin levels and other clinical measures in serum [Anti Cyclical Citrullinated Peptide Antibody (ACCP), Rheumatoid Factor (RF)] were determined by quantitative enzyme-linked immunosorbent assay (ELISA). The sensitivity and specificity of vimentin was determined by Receiver-operating characteristic (ROC) curves analysis. The relationship between serum and salivary level of vimentin in RA patients with other clinical measures was assessed by Spearman's rank correlation coefficient. Results: (Mean +/- SD; Median) of serum vimentin concentration (mg/ml) in RA patients was (21.974 +/- 12.639; 23.096) which was significantly higher than in healthy subjects (6.704 +/- 2.720; 6.031; P<0.001). Patients with RA and controls were compared by using ROC curve analysis, showed a significant (P<0.001); ROC curve showed that area under the curve (AUC) of 0.929 (95% confidence interval: 0.869-0.990). At a cut-off of 6.5 mg/mL, serum vimentin had a sensitivity of 91.3% and specificity of 80%. (Mean +/- SD; Median) of salivary vimentin concentration (mg/ml) in RA patients (8.059 +/- 4.943; 6.295) was higher than that in healthy subjects (6.436 +/- 4.477; 5.232) with no significant result statistically. ROC was drawn to make comparison between RA patients with controls, showed a significant (P<0.001); ROC curve showed that area under the curve (AUC) of 0.918 (95% confidence interval: 0.0794-1.000). At a cut-off of 5.5 mg/mL, salivary vimentin had a sensitivity of 98.6% and specificity of 60 %. The results show levels of salivary vimentin was no significantly correlated with levels of serum vimentin. However, serum vimentin positively correlated with serum anti cyclic Citrullinated peptide (ACCP) (r=0.522, P<0.001) and serum rheumatoid factor (RF) (r=0.430, P<0.001), but no significant result with 28-joint disease activity score (DAS) in patients with RA. Conclusions: Vimentin in serum is useful than salivary vimentin to detect patient with rheumatoid arthritis.