OP0252 CIRCULATING COLLAGEN TURNOVER MARKERS ARE SPECIFICALLY CHANGED IN VERY EARLY SYSTEMIC SCLEROSIS
Authors: R. Dobrota, S. Jordan, P. Juhl, B. Maurer, M. O. Becker, C. Mihai, A. C. Bay-Jensen, M. Karsdal, A. S. Siebuhr, O. Distler
Journal: Annals of the Rheumatic Diseases (2020)

Background: Timely diagnosis of patients with very early systemic sclerosis (veSSc) is essential for their personalized and optimal management. We hypothesise that changes in serum-based extracellular matrix (ECM) turnover biomarkers are already detectable in patients with veSSc, even before occurrence of specific clinical signs. Objectives: To investigate circulating ECM turnover markers as potential biomarkers for veSSc. Methods: Patients with veSSc, n=42, defined as presence of Raynaud’s syndrome and at least one of puffy fingers, positive antinuclear antibodies or pathological nailfold capillaroscopy, who did not meet any classification criteria for SSc, were compared to healthy controls (HC, n=29). Longitudinal assessment, data and sera collection were conducted by EUSTAR standards. ECM-degradation (BGM, C3M, C4M, C6M) and ECM-formation biomarkers (PRO-C3, PRO-C4, PRO-C5) were measured in serum using ELISA assays. The statistical analyses included Mann-Whitney U, Spearman correlation and ROC analysis. Using Kaplan-Meier plots and univariable Cox regression, we explored if biomarkers can predict progression towards definite SSc (fulfillment of ACR/EULAR criteria or minimum two points increase in the criteria score) during the longitudinal follow-up. Results: Compared to HC, veSSc patients showed a deregulated turnover of type III and IV collagen, with higher degradation (higher C3M, C4M, both p&lt;0.0001 and PRO-C3, p=0.004, Figure 1a, resulting in lower turnover ratios PRO-C3/C3M and PRO-C4/C4M, both p&lt;0.0001). The biglycan degradation biomarker BGM was also higher in veSSc (p=0.006), whereas the degradation biomarker for type VI collagen, C6M, was lower than in HC (p=0.002). In the ROC analysis, biomarkers of type III and IV collagen distinguished between veSSc and HC: C3M, AUC=0.95, p&lt;0.0001; C4M, AUC=0.97, p&lt;0.0001; turnover ratios PRO-C3/C3M, AUC=0.80, p&lt;0.0001; PRO-C4/C4M, AUC=0.97; p&lt;0.0001 (Figure 1b). Median follow up was 4.5 years (range 0.5-7.9 years), mean age was 50±2.2 years, 88% female gender, 24% with puffy fingers, 92% were ANA positive, 64% had an abnormal capillaroscopy, none had organ involvement or skin fibrosis. 14/42 veSSc patients fulfilled the ACR/EULAR classification criteria at follow-up (time to fulfilment of criteria ranged between 0.5 and 6.8 years from inclusion) and in addition, 18/42 veSSc patients gained at least two classification criteria-points. This resulted in 14, respectively 18 progressors for the longitudinal analysis. However, in univariable Cox regression, the baseline levels of the markers did not predict progression over time. Conclusion: ECM turnover is already altered in veSSc patients compared to HC. Biomarkes of type III and IV collagen distinguished between veSSc patients and HC, which may indicate them as potential biomarkers for the detection of veSSc in addition to the established immunological and capillaroscopic criteria. Disclosure of Interests: Rucsandra Dobrota: None declared, Suzana Jordan: None declared, Pernille Juhl Employee of: Nordic Bioscience, Britta Maurer Grant/research support from: AbbVie, Protagen, Novartis, congress support from Pfizer, Roche, Actelion, and MSD, Speakers bureau: Novartis, Mike O. Becker: None declared, Carina Mihai: None declared, Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S., Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Anne Sofie Siebuhr Employee of: Nordic Bioscience, Oliver Distler Grant/research support from: Grants/Research support from Actelion, Bayer, Boehringer Ingelheim, Competitive Drug Development International Ltd. and Mitsubishi Tanabe; he also holds the issued Patent on mir-29 for the treatment of systemic sclerosis (US8247389, EP2331143)., Consultant of: Consultancy fees from Actelion, Acceleron Pharma, AnaMar, Bayer, Baecon Discovery, Blade Therapeutics, Boehringer, CSL Behring, Catenion, ChemomAb, Curzion Pharmaceuticals, Ergonex, Galapagos NV, GSK, Glenmark Pharmaceuticals, Inventiva, Italfarmaco, iQvia, medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Roche, Sanofi and UCB, Speakers bureau: Speaker fees from Actelion, Bayer, Boehringer Ingelheim, Medscape, Pfizer and Roche