POS0460 ASSOCIATION OF ANTI-CITRULLINATED PROTEIN ANTIBODIES OF IgA SUBCLASSES WITH SUSTAINED REMISSION AND FLARE IN RHEUMATOID ARTHRITIS

Background: Understanding key mechanisms of flare development and sustained remission is one the acute goals in modern rheumatology. Anti-citrullinated protein antibodies (ACPA) are most abundant specific autoantibodies rheumatoid arthritis (RA) patients. However, impact ACPA IgA isotype poorly defined. were previously shown to have a higher percentage IgA2 comparison total IgA; correlation between IgA2% with DAS28 score was observed previous study [1]. Of note, IgA1 exhibit different effector functions, being pro-inflammatory, which might be background for its role RA Objectives: We aimed investigate, whether could used as predictive factor RA; look further into changes levels patients remaining stable versus developing flare. Methods: analysed serum 111 from multicentre randomized controlled trial ‘RETRO’. The observational period 12 months. Patients had (DAS28-ESR<2.6) minimum 6 months 3 treatment arms: continuation treatment, tapering by 50% or gradual until discontinuation [2]. concentrations measured an enzyme-linked immunosorbent assay on CCP2-pre-coated plates. Results: 60% IgG-ACPA. among IgG-ACPA-positive (median 4.7 2.24 µg/ml, p<0.0001). Baseline 2 not who later those remission, showing no value development. correlating first registered after (r=0.36, p=0.046). After period, well decreased significantly remained 17.5% (median, p<0.0001) 13.6% (p=0.0006), respectively. By contrast, there significant change over time developed time. Disease management strategies did seem influence way, baseline similar biological conventional DMARDs depend assignment either arms. Conclusion: Neither nor associated (though rituximab, JAK-inhibitors abatacept amongst options). 1 year decrease This indication towards contributing severity flare, alongside other factors, reduction prolonged state remission. References: [1]Steffen U, Koeleman CA, Sokolova MV, et al. subclasses functions distinct glycosylation profiles. Nat Commun 11, 120 (2020). [2]Haschka J, Englbrecht M, Hueber AJ, Relapse rates stopping antirheumatic therapy: interim results prospective randomised RETRO study. Ann Rheum Dis. 75:45-51 (2016). Disclosure Interests: None declared