POS0189 SERUM IFNα CONCENTRATIONS MEASURED WITH SINGLE-MOLECULE ARRAY TECHNOLOGY IN SJÖGREN’S SYNDROME REFLECT BLOOD INTERFERON-STIMULATED GENE EXPRESSION

Background: Type I interferon (IFN-I) activation is a prominent feature of several Rheumatic and Musculoskeletal Diseases (RMDs) including primary Sjögren’s syndrome (pSS), systemic lupus erythematosus (SLE) sclerosis (SSc). Ultrasensitive single-molecule array (SiMoA) technology has facilitated the measurement subfemtomolar concentrations IFNs [1-3]. Objectives: Here, we tested performance commercially available SiMoA kit for detection IFNα in serum from pSS, SLE, SSc correlated to whole blood IFN-stimulated gene (ISG) expression. Methods: Serum IFNα2 was measured healthy controls (HC; n=68) patients with pSS (n=85, n=110), SLE (n=24) (n=23) using ready-to-use on HD-X Analyzer. IFN-I additionally determined paired samples expression IFI44, IFI44L, IFIT1, IFIT3, MxA by RT-PCR or MxA-ELISA. Results: levels were elevated (median = 61.3 fg/mL) compared HC < 5fg/mL) 11.6 fg/mL), lower 313.5 positively ISG (rs=0.71-0.76, p<0.001). Comparable MxA-ELISA (AUC=0.93), identified high (AUC=0.90) 80-93% specificity 71-84% sensitivity. Blinded validation an independent cohort yielded comparable accuracy 89%. Multiple linear regression indicated associations autoantibodies, IgG, use hydroxychloroquine pSS. Confirming literature [4], remission (DORIS classification) not remission. Conclusion: Thus, reflects SSc. In light IFN-targeting treatments, could potentially be applied patient stratification high-throughput retrospective analysis stored clinical trial material. References: [1]Rissin, D.M.; Kan, C.W.; Campbell, T.G.; Howes, S.C.; Fournier, D.R.; Song, L.; Piech, T.; Patel, P.P.; Chang, Rivnak, A.J., et al. Single-molecule enzyme-linked immunosorbent assay detects proteins at concentrations. Nat. Biotechnol. 2010, 28, 595-599. [2]Wilson, D.H.; Rissin, Meyer, R.E.; Fishburn, M.W.; Cabrera, C.; P.P., The Simoa HD-1 Analyzer: A Novel Fully Automated Digital Immunoassay Analyzer Single-Molecule Sensitivity Multiplexing. Journal Laboratory Automation 2015, 21, 533-547. DOI: 10.1177/2211068215589580. [3]Rodero, M.P.; Decalf, J.; Bondet, V.; Hunt, D.; Rice, G.I.; Werneke, S.; McGlasson, S.L.; Alyanakian, M.A.; Bader-Meunier, B.; Barnerias, C., Detection alpha protein reveals differential cellular sources disease. J. Exp. Med. 2017, 214, 1547-1555. 10.1084/jem.20161451. [4]Mathian, A.; Mouries-Martin, Dorgham, K.; Devilliers, H.; Yssel, Garrido Castillo, Cohen-Aubart, F.; Haroche, Hie, M.; Pineton de Chambrun, M., interferon-alpha quantification during identifies risk relapse. Ann. Rheum. Dis. 2019, 78, 1669-1676. 10.1136/annrheumdis-2019-215571. Disclosure Interests: None declared