Abstract
OBJECTIVES
To analyse the predictive value of anti-carbamylated protein (anti-CarP) and anti-peptidyl-arginine deiminase type-3 (anti-PAD3) antibodies, alone or in combination with rheumatoid factors (RFs) and anti-citrullinated protein antibodies (ACPA), to identify patients at high risk of developing severe rheumatoid arthritis (RA) outcomes.
METHODS
Patients within the « Swiss Clinical Quality Management » registry with a biobank sample were tested for RFs, ACPA, anti-CarP, and anti-PAD3 antibodies. We examined the association of each autoantibody with DAS28, HAQ and radiographic damage (Ratingen) at baseline and longitudinally.
RESULTS
Analyses included 851 established RA patients and 516 disease controls [axial spondyloarthritis (axSpA = 320) and psoriatic arthritis (PsA = 196)]. Anti-CarP and anti-PAD3 antibodies were respectively present in 22.4% and 10.7% of the whole RA population, and in 13.2% and 3.8% of the RF and ACPA double seronegative patients. At baseline, RA patients with anti-PAD3 had higher DAS28 (4.2 vs 3.7; p = 0.005) and significantly more radiographic damage (14.9 vs 8.8; p = 0.02) than anti-PAD3 negative patients. In ACPA negative subgroup, baseline Ratingen scores were significantly higher in anti-PAD3 positive patients (p = 0.01). The combination of anti-PAD3, RF IgM, and ACPA was associated with significantly higher baseline radiographic scores than the double seropositive group (p = 0.04). The presence of any two of the previous autoantibodies was associated with significantly greater radiographic progression over 10 years than if all were absent (p = 0.02). There were no differences on RA outcome measures with regards to anti-CarP.
CONCLUSIONS
Anti-PAD3 antibodies are associated with higher disease activity and joint damage scores in RA patients.
Lamacchia, Celine