POS0103 IN RHEUMATOID ARTHRITIS, THE ASSOCIATION BETWEEN ANTI-MODIFIED PROTEIN ANTIBODIES AND LONG-TERM OUTCOMES IS DOMINATED BY THE EFFECT OF ANTI-CITRULLINATED PROTEIN ANTIBODIES

Background In rheumatoid arthritis (RA) many patients harbor autoantibodies against post translationally modified proteins (anti-modified protein antibodies (AMPA)): anti-citrullinated (ACPA), anti-carbamylated (anti-CarP) and anti-acetylated (AAPA). All three AMPA have been described to be associated with an increase in radiographic joint damage ACPA also a lower chance of obtaining sustained drugfree remission (SDFR). However, it is unclear whether the effects these are independent each other, testing for all offers additional information regarding clinical outcomes. Objectives To investigate individual combined associations radiological progression SDFR RA. Methods 612 RA from Leiden Early Arthritis Clinic, we measured IgG anti-CCP2-assays, anti-CarP using homocitrullinated native (as control) fetal calf serum, AAPA by means novel assays consisting cyclic peptides either acetylated or norleucine residues control). Sharp-van der Heijde scores (SHS) were determined 2685 sets radiographs yearly intervals 7 years. The association SHS was assessed multivariate normal regression model. defined as absence synovitis after discontinuation DMARD treatment. autoantibody-status Kaplan-Meier curves. very small number single-positive (n=4, 1%) precluded analyses this subgroup. Results prevalence shown Table 1. A higher found compared without antibodies, triple-positive versus (Figure 1A, p=0.04). if due specific autoantibody, stratified AMPAs. Interestingly, no difference between ACPA-positive strata 1B). ACPA-negative stratum, significant zero solely (p=0.02). Prevalence EAC cohort Autoantibody status n (%) 316 (52) Anti-CarP-positive 270 (44) AAPA-positive 208 (34) ACPA-AAPA-CarP- 255 (42) ACPA+ AAPA-CarP- 46 (7) ACPA- AAPA+ CarP- 4 (1) ACPA-AAPA- CarP+ 37 (6) ACPA+AAPA+ AAPA- 66 (11) -AAPA+CarP+ - (0) ACPA+AAPA+CarP+ 167 (27) EAC: early clinic, ACPA: anti-CarP/CarP: AAPA: obtain antibody-positive groups autoantibody negative group. Moreover less triple-antibody-positive than single-antibody-positive achieved (P<0.001), Figure 1C. After stratification AMPA, percentage strata, 1D. Conclusion patients, presence other influences neither progression, nor SDFR. Thus, long-term phenotype particularly dependent on ACPA, AMPA. Therefore, there appears added value predicting outcome patients. Disclosure Interests None declared