AB0077 Soluble urokinase plasminogen activator receptor (supar) for monitoring inflammatory activity in different rheumatic diseases

Background suPAR is a biomarker increasingly used for the monitoring of systemic inflammation. Activation of the immune system leads to elevated serum suPAR. We aimed to evaluate suPAR for the monitoring of inflammatory activity in different rheumatic diseases including rheumatoid arthritritis (RA), systemic lupus erythematosus (SLE) and anklyosing spondylitis (AS). Methods Serum suPAR, CRP and ESR were measured in 120 RA, 89 SLE and 33 AS patients with various disease activity and in healthy age-matched controls. Results suPAR, CRP and ESR were higher in RA patients than in controls (4.24 [3.19-5.40] vs 2.80 [2.06-3.42] ng/mL 4.00 [0-9.83] vs 2.70 [0-4.15] mg/L and 21 [12-36.5] vs 10 [7-14] mm/h respectively p 2.6, but still higher than in controls (4.45 [3.33-5.56] vs 3.66 [3.10-4.67] vs 2.80 [2.06-3.42] ng/mL p 8 was regarded as high disease activity. In case of CRP and ESR, no difference was detected according to SLEDAI. However, suPAR in patients with SLEDAI>8, were higher than in patients with SLEDAI 1-8 or 0. CRP and ESR were higher in AS patients than in controls, while suPAR were comparable (2.97 [2.57-3.80] vs 2.80 [2.06-3.42] ng/mL p>0.05). In AS patients, a correlation was detected between BASDAI indices and CRP as well as ESR but not suPAR. Conclusions While the normalisation of CRP and ESR values suggest remission of the chronic inflammatory process in RA, suPAR values are still elevated compared to controls. suPAR is a sensitive and stable marker of inflammation in the monitoring of RA patients. It is especially valuable in the recognition of inflammatory activity in patients who are in remission according to DAS28 scores but have symptoms of TJ/SJ. While CRP and ESR values showed no differences according to SLEDAI, suPARs correlated with higher SLEDAI. Therefore, the monitoring of suPAR might be a useful tool for the follow-up of patients with mild symptoms but ongoing chronic inflammation in RA and a useful, objective marker for higher disease activity in SLE. Unlike plasma suPAR levels do not reflect inflammation in AS. Disclosure of Interest None Declared