Antibodies to mutated citrullinated vimentin in rheumatoid arthritis: diagnostic value, association with radiological damage and axial skeleton affection.

Background: Early definitive diagnosis and effective treatment are mandatory in rheumatoid arthritis (RA) as it can halt the disease progression and subsequent joints destruction.

Objective: To investigate the diagnostic and prognostic value of anti-mutated citrullinated vimentin (anti-MCV) and its correlation with disease activity, peripheral and axial skeleton affection in RA patients.

Patients And Methods: A total of 123 patients with different rheumatic diseases were enrolled in a prospective-two year study at Ain Shams University hospital: 64 patients with RA and 59 patients with other rheumatic diseases as controls. RA patients were fulfilling the traditional and the new ACR/EULAR diagnostic criteria for RA. They have been followed up for two years. At baseline, all RA patients were subjected to: Clinical assessment of disease activity by taking full histories, general and local examination, measurement of 28 joint count of tender and swollen joints with calculation of disease activity score (DAS-28) for each patient. Complete blood count, erythrocytes sedimentation rate, C-reactive protein and rheumatoid factor titers were performed. Anti-MCV IgG immunoglobulins' assay was performed at the study endpoint by ELISA. RA patients were then classified into; anti-MCV positive and anti-MCV negative groups for statistical comparison. Plain X-ray was performed on the peripheral joints and scored by the Simple Erosion Narrowing score (SEN-score). Magnetic Resonance Imaging (MRI) scans were carried out to 22 RA patients on cervical and lumbosacral regions.

Results: Anti-MCV antibodies were found to be of high sensitivity (79.6%) and specificity (96.6%) in diagnosing RA. The area under the curve was 0.893 at 95% confidence interval (CI), confers an odds ratio of 23.5. Anti-MCV positive RA patients had significantly higher DAS-28 and SEN-scores than anti-MCV negative patients; who were found to have more benign disease with lower incidence of erosions (P < 0.05). MRI scans revealed that; 17/22 (77%) had cervical joints involvement while, 8 (36%) had lumbo-sacral joint lesions (P < 0.05), both were correlated significantly with aggressive peripheral joint disease.

Conclusion: Anti-MCV antibodies are promising diagnostic and prognostic marker in RA, with high sensitivity and specificity. They may identify a subset of RA patients with aggressive early erosive disease. The axial skeleton-especially the cervical spine-could be affected in RA and this was correlated with aggressive peripheral joints' disease. MRI scanning is a sensitive method for detecting axial skeleton involvement in RA, in attempt for better disease control and outcomes.