Objectives To analyse clinical, serological and sonographic differences in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) on anti-TNF therapy.
Methods Patients diagnosed with RA or PsA in clinical remission (DAS28-ESR<2.6) on anti-TNF therapy were included. Angiogenic and proinflammatory cytokines were determined by Multiplex ELISA and compared with the same measurement in two control cohorts: active RA patients (DAS28>3.2) and healthy people. Ultrasound scans of both hands were performed in all participants, with scoring of synovial hypertrophy (SH) (grades 0-3) and power Doppler (PD) signal (grades 0-3).
Results 30 RA and 47 PsA patients in clinical remission, 22 clinically-active (DAS28-ESR>3.2) RA patients and 20 healthy controls were included. RA patients in clinical remission had significantly higher disease activity (2.01 and 1.74, mean DAS28-ESR for RA and PsA, respectively, p=0.006) and higher levels of both proinflammatory (IL6, TNF, IL17F, IL23 and IL33) and angiogenic cytokines (Angiogenin, ANGPTL4, CXCL16, ENA78, PIGF and SDF1) compared with PsA patients in clinical remission. No differences were found in these mediators between PsA and healthy controls, whereas in RA patients in clinical remission these mediators were more similar to clinically active RA.
Globally, 31 patients had a PD signal and 12 had SH≥2 plus PD, meeting the criteria of ultrasound-defined active synovitis (UdAS)]. Only 1 PsA patient met UdAS criteria compared with 11 RA patients in clinical remission (p=0.0001). Patients with UdAS had significantly higher levels of IL-6, IL-20, PIGF and SDF1. More PsA patients were receiving low doses of biologics (63.8%), and more frequently as monotherapy (72.3%) compared with RA patients in clinical remission (26.6% and 20%, respectively).
Conclusions Clinical remission is qualitatively different in RA and PsA receiving TNF antagonist therapy. PsA patients had significantly-lower serum levels of angiogenic and proinflammatory cytokines and less ultrasound synovitis than RA patients. A significantly-higher percentage of PsA patients were receiving low doses of biologics, mainly with monotherapy compared with RA patients in remission. Patients with chronic inflammatory polyarthritis in clinical remission with UdAS had higher serum levels of angiogenic/proinflammatory biomarkers, supporting the idea that this reflects true active synovitis.
Disclosure of Interest None declared