Diagnostic value of rheumatoid factor, antikeratin antibodies and anticyclic citrullinated peptide antibodies in rheumatoid arthritis : association with erosive articular damage

الملخص EN

Background : Various autoantibodies have been described in the serum of rheumatoid arthritis (RA) patients such as rheumatoid factor (RF), ant keratin antibodies (AKA) and anti-cyclic citrullinated peptide antibodies (anti-CCP).

Objective: this work was performed to assess and compare the diagnostic value of RF, AKA and anti-CCP in RA, and to identify their predictive value for erosive articular damage in patients with RA.

Methodology : the study was carried out on 50 patients, 30 RA patients and 20 patients with other different rheumatic disorders who served as a control group.

RA patients were 15 with early RA (< 2 years disease duration) and 15 with late RA (> 2 years).

Serum samples from all 50 patients were subjected to detection of IgM RF and anti-CCP by enzyme linked immunosorbent assay (ELISA) and AKA by indirect immunofluorescence.

Erosive articular damage was quantified using the Larsen score.

Results : positive anti-CCP was found in 23 out of 30 RA patients and in 2 out of 20 controls with the highest sensitivity and specificity for RA 76.7 % and 90 %, respectively.

IgM RF was positive in 21 out of 30 RA patients and in 3 out of 20 controls with sensitivity and specificity of 70% and 85%, respectively.

Lastly AKA was positive in 16 out of 30 RA patients and 4 out of 20 controls with the lowest sensitivity and specificity for diagnosis of RA 53.3 % and 80 %, respectively.

Significant lower percentage of positivity for both AKA and IgM RF in early RA compared to late RA (p < 0.01) but not for anti-CCP (p > 0.05).

Patients with positive antibodies had significantly higher erosion score than those with negative ones, p < 0.01 for both IgM RF and AKA and p < 0.001 for anti-CCP.

Conclusions : Anti-CCP show the highest sensitivity and specificity for RA followed by IgM RF and lastly AKA.

All the studied antibodies particularly anti-CCP may help in the early diagnosis and can be considered as predictive markers for erosive articular damage in RA patients.