SAT0003 Quantitative Monocyte CD64 (MCD64) Expression is Useful Biomarker for Disease Activity in Systemic Lupus Erythematosus (SLE) Patients. (10th June 2014)

• Record Type: Journal Article
• Authors: Yura, A.; Tsuji, S.; Kitatoube, A.; Kikuchi-Taura, A.; Katayama, M.; Watanabe, A.; Teshigawara, S.; Yoshimura, M.; Kudo-Tanaka, E.; Harada, Y.; Matsushita, M.; Katada, Y.; Ohshima, S.; Hashimoto, J.; Saeki, Y.
• Is Part Of: Annals of the rheumatic diseases. Volume 73:Supplement 2(2014)
• Page Start: 590
• Page End: 591
• Publication Date: 2014-06-10
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2014-eular.2824
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: Interferon (IFN)-α has been largely implicated in the ethiopathogenesis of SLE. The activation of IFN-α might be important in the prognosis and activity assessment of the disease. CD64 (FcγRI) is upregulated on monocytes as a response to IFN-I 1 . Flow cytometry analysis of mCD64 expression (Mean Fluorescence Intensity) is a convenient and rapid approach for estimating IFN-α levels in SLE patients. Additionally, macrophage colony-stimulating factor (M-CSF), which is involved in the differentiation of monocyte/macrophage, affects CD64 expression on monocyte 2 has been reported to increase in levels in SLE patients, 3 and is also involved in SLE disease activity 4 . mCD64 can be the quantified easily and the measurement is consistent among the respective facilities. However, the quantitative mCD64 of SLE patients has not been reported. Objectives: We investigated the levels of mCD64 by quantitative flow cytometry to assess the usefulness of it as a SLE disease activity biomarker. Methods: 30 SLE patients (10 active SLE, 20 inactive SLE) and 20 healthy controls (HC) were in this study. SLE disease activity was evaluated using by SLE-Disease Activity Index (SLEDAI) score. mCD64, SLE activity biomarkers (anti-DNA antibody and complement titer (CH50)), IFN-α and M-CSF were measured in SLE patients. mCD64 was measured by a quantitative flow cytometry using fluorescene microbeads. INF-α and M-CSF levels were measured using an enzyme-linked immunoabsorbent assay (ELISA). Correlational analysis between levels of mCD64, SLEDAI, SLE activity biomarkers, INF-α and M-CSF in each group were evaluated. Results: Disease activity markers are shown Table 1 . The variables with significant difference between active SLE and inactive SLE were SLEDAI (p<0.05), CH50 (p<0.05), anti DNA antibody (p<0.05), mCD64 (p<0.05), IFN-α (p<0.05), M-CSF (p<0.05).mCD64 levels were correlated with SLEDAI (r=0.6669, p<0.001), anti-DNA antibody (r=0.6887, p<0.05) and CH50 (r=-0.6928, p<0.001), but were not correlated with C3 or C4 levels (data not shown). Further, mCD64 levels were correlated with IFN-α (r=0.6089, p<0.001) and M-CSF (r=0.64443, p<0.001) Conclusions: This study suggests that quantitative CD64 molecules expressed on monocytes can be a useful disease activity biomarker in SLE patients. References: Li, Y. et al. Arthritis Research & Therapy 2010, 12:R90 Ji XH et al. Acta Pharmacol Sin. 2004; 25(10): 1361-5 Yang PT et al. Ann Rheum Dis. 2008, 67(3): 429-30 Tsuji S. et al. The Journal of Tokyo Medical University vol.70, No.1: 151-8 Disclosure of Interest: None declared DOI: 10.1136/annrheumdis-2014-eular.2824