Session Type: Abstract Submissions (ACR)
Presence of anti citrullinated-protein antibodies (ACPA) in the peripheral blood of patients with rheumatoid arthritis is a validated disease biomarker. We have previously shown local synovial production of these antibodies in the synovial fluid of active RA. We aimed to investigate longitudinal stability of ACPA and ACPA fine specificities in SF of active established RA patients.
A cohort of 30 RA patients (n=30) with established RA (median disease duration 11 years at inclusion) was followed up for a median of 9 years. Half of the included patients were testing positive for CCP2 ELISA in the SF when screened at one arbitrary time point and half were negative. Longitudinal SF samples of these patients (a median of 5 samples/patient, median follow-up time of 9 years) were analyzed for the presence of anti CCP2 antibodies and for fine ACPA specificities using ELISA against citrullinated forms of alpha-enolase (aa5-21; cep-1), fibrinogen (aa566-580; cit-fib573) and vimentin (aa60-75; cit-vim60-75) peptides. Cut off of these ELISAs were set at the 98th percentile, based on analysis of sera from healthy controls.
SF ACPA quantification using the CCP2 ELISA kit demonstrates a highly stable phenotype during time, with all patients selected on the basis of ACPA positivity at one time point (15/30, 100%) being positive on all tested occasions. The same was true for ACPA negative SF (15/30, 100%). Among fine specificities presence of anti citrullinated a-enolase was stable (with 5/30 positive and 25/30 negative patients on all tested occasions). Same trend was observed for antibodies against citrullinated vimentin with 25/30 patients being either positive (3) or negative (22) on all tested occasions and citrullinated fibrinogen with 28/30 patients being either positive (3) or negative (24) on all tested occasions.
Conclusion: We demonstrate that both ACPA and ACPA fine specificities have a stable phenotype in SF of patients with longstanding RA suggesting continuous local production of antibodies during disease progression.
Janssen Research and Development, LLC,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/stable-synovial-fluid-phenotype-for-anti-citrullinated-protein-antibodies-in-established-rheumatoid-arthritis/