Anti carbamylated protein antibodies as a diagnostic marker in patients with rheumatoid arthritis and its association with disease activity

Abstract

Abstract Background Despite the diagnostic contribution of anti-citrullinated protein( anti-CCP) antibody and rheumatoid factor (RF), approximately one-third of patients with rheumatoid arthritis (RA) remain seronegative .Anti-carbamylated protein (Anti-Carp) antibodies have been attracting increasing attention as a new diagnostic marker of RA. Objective evaluate levels of anti-carp antibodies in RA patients in order to detect its role as a diagnostic marker and its possible association with disease activity and severity. Methods This study included thirty adult patients with clinical evidence of rheumatoid arthritis and thirty healthy matched age and sex as controls. All underwent history taking, clinical examination, assessment of disease activity with modified Disease Activity28 (DAS28), Laboratory investigations including Complete blood count (CBC), erythrocytes sedimentation rate (ESR), C-Reactive Protein (CRP), Liver function tests, Kidney function tests, Serum uric acid, RF, anti CCP Ab, anti-Carp Ab and radiographic Assessment with Larsen score. Results Plasma levels of anti-Carp Ab were significantly higher in patients than control group (p > 0,001) with sensitivity of 73.33% and specificity of 100%.it showed significant positive correlation with CRP (r = 0.37 )(p < 0.05) as a marker of activity of RA and also there was significant positive correlation with RF and ACPA (r = 0.45)(r = 0.48) (p < 0.05) respectively as a diagnostic marker for RA. Plasma levels of anti-Carp Ab were higher in patients with more joints damage and erosions as assessed by Larsen radiological score as there was a highly significant correlation between Larsen score and serum Anti-Carp(r = 0.61)(p < 0.001).. Conclusion serum Anti–Carp antibody level was higher in RA patients which serve as a diagnostic marker for RA, also its significant correlation with CRP and Larsen score may serve as a marker for disease progression and severity.