PT - JOURNAL ARTICLE AU - Thomas Rose AU - Andreas Grützkau AU - Heike Hirseland AU - Dörte Huscher AU - Cornelia Dähnrich AU - Andrzej Dzionek AU - Tobias Ozimkowski AU - Wolfgang Schlumberger AU - Philipp Enghard AU - Andreas Radbruch AU - Gabriela Riemekasten AU - Gerd-Rüdiger Burmester AU - Falk Hiepe AU - Robert Biesen TI - IFNα and its response proteins, IP-10 and SIGLEC-1, are biomarkers of disease activity in systemic lupus erythematosus AID - 10.1136/annrheumdis-2012-201586 DP - 2013 Oct 01 TA - Annals of the Rheumatic Diseases PG - 1639--1645 VI - 72 IP - 10 4099 - http://ard.bmj.com/content/72/10/1639.short 4100 - http://ard.bmj.com/content/72/10/1639.full SO - Ann Rheum Dis2013 Oct 01; 72 AB - Objectives To evaluate and compare the clinical efficacy of three biomarkers for interferon (IFN) activity (measured directly and indirectly) and six traditional biomarkers in indicating current and prospective disease activity (DA) in systemic lupus erythematosus (SLE). Methods IFNα (dissociation-enhanced lanthanide fluorescent immunoassay), IFNγ-inducible protein 10 (IP-10) (ELISA) and sialic acid-binding Ig-like lectin 1 (SIGLEC-1) (flow cytometry) were measured in 79 accurately characterised patients with lupus and compared with serum titres of Anti-dsDNA (ELISA and radioimmunoassay), Anti-dsDNA-NcX ELISA, Anti-Nuc ELISA, and complement C3 and C4. DA was evaluated using the British Isles Lupus Assessment Group 2004 Index (BILAG-2004) and a modified SLE Disease Activity Index-2000 (mSLEDAI-2K). In addition, 31 clinically quiescent patients were monitored for flares over the course of 180 days. Results Increased levels of IFNα, IP-10 and SIGLEC-1 were found in 32%, 50% and 86%, respectively, of 66 patients with active SLE. IFNα (r=0.45; p<0.0001) and SIGLEC-1 (r=0.54; p<0.0001) correlated better with BILAG-2004 than did IP-10 (r=0.38; p=0.0002), Farr assay (r=0.40; p=0.0001), Anti-dsDNA-NcX ELISA (r=0.28; p=0.0061), Anti-dsDNA ELISA (r=0.31; p=0.0025), Anti-Nuc ELISA (r=0.25; p=0.0121), C3 (r=−0.43; p<0.0001) and C4 (r=−0.33; p=0.0013). Predictors of SLE flares were disease duration ≤92 months, mild clinical activity (in contrast with no activity), complement C3≤89 mg/dl and IFNα≥20 pg/ml, while only lymphocyte count and age were independent predictors in multivariate analysis. Conclusions IFNα, IP-10 and SIGLEC-1 emerged as beneficial biomarkers of DA in patients with SLE. Therefore the implementation of IFN biomarkers in standard lupus diagnostics should be reappraised, especially in view of emerging anti-IFN-directed therapies.