AB0347 CLINICAL RELEVANCE OF ANTI-CARBAMYLATED PROTEIN ANTIBODY: IS IT SAME AS CAUCASIANS IN ASIANS?

Background Recently, there was an interesting study demonstrating that anti-CarP was associated with more inflammation and higher baseline disease activity in French ESPOIR cohort [1]. However, all of the investigated patient cohorts have been Caucasian. However, considering the genes associated with RA are different in Caucasians and Asians, PTPN22 in Caucasians and PADI4 in Asians, and those genes contribute to the loss of tolerance and autoantibody production, clinical relevance of anti-CarP might be different in Asians. Objectives Therefore, we investigated the clinical significance of anti-CarP in Korean patients with early RA focused on initial presentations and treatment outcome. Methods The anti-CarP antibodies were analysed by commercial ELISA (Novateinbio, USA) in the Korean Intensive Management of Early Rheumatoid Arthritis cohort. All patients were DMARD-naive RA patients with symptom duration less than 1 year. They were intensively treated by adjusting medications every 4 weeks, and treated to target as disease activity score (DAS)28 of Results A total of 128 patients were included, 67 patients (52.3%) were positive for anti-CarP antibody at presentation. After 2 years of treatment, proportion of anti-CarP positivity decreased to 38.1% (p=0.049), but titration did not change (6.87 to 4.45 ng/ml, p=0.074). Patients without anti-CarP antibody presented with more tender joint count (TJC) (7.3 vs. 5.2, p=0.055), swollen joint count (SJC) (4.1 vs. 2.6, p=0.019) and higher baseline physician global VAS (5.5 vs 4.7, p=0.005) than patients with anti-CarP antibody. Subgroup analysis with ACPA negative patients, patients without anti-CarP antibody showed more TJC (13.7 vs. 4.7, p=0.043), SJC (7.9 vs. 3.0, p=0.076), higher patient global VAS (5.9 vs. 3.7, p=0.044) and DAS28-ESR (6.1 vs. 4.7, p=0.051). After intensive treatment, there were no differences in remission rate and DAS28-ESR at 12, 24, and 36 months. Conclusion Interestingly, RA patients without anti-CarP antibody presented with more TJC/SJC than those with anti-CarP antibody in Korean patients. This finding is contrast to previous studies which were done with Caucasians. Further investigation is needed to conclude the clinical implications of anti-CarP. References [1] Truchetet ME, Dublanc S, Barnetche T, Vittecoq O, Mariette X, Richez C, et al. Association of the Presence of Anti-Carbamylated Protein Antibodies in Early Arthritis With a Poorer Clinical and Radiologic Outcome: Data From the French ESPOIR Cohort. Arthritis Rheumatol 2017;69(12):2292-302. Disclosure of Interests None declared