%0 Journal Article
%T Monocyte surface expression of Fc¦Ã receptor RI (CD64), a biomarker reflecting type-I interferon levels in systemic lupus erythematosus
%A Yi Li
%A Pui Y Lee
%A Erinn S Kellner
%A Matthew Paulus
%A Juliana Switanek
%A Yuan Xu
%A Haoyang Zhuang
%A Eric S Sobel
%A Mark S Segal
%A Minoru Satoh
%A Westley H Reeves
%J Arthritis Research & Therapy
%D 2010
%I BioMed Central
%R 10.1186/ar3017
%X Monocyte surface expression of Fc¦Ã receptors (Fc¦ÃRs), chemokine receptors, and activation markers were analyzed with flow cytometry in whole blood from patients with SLE and healthy controls. Fc¦ÃR expression also was measured in peripheral blood mononuclear cells (PBMCs) from healthy controls cultured with Toll-like receptor (TLR) agonists, cytokines, or serum from SLE patients. Expression of ISGs was analyzed with real-time PCR.Circulating CD14+ monocytes from SLE patients showed increased surface expression of Fc¦ÃRI (CD64). The mean fluorescent intensity of CD64 staining correlated highly with the ISG expression (MX1, IFI44, and Ly6E). In vitro, IFN-I as well as TLR7 and TLR9 agonists, induced CD64 expression on monocytes from healthy controls. Exposure of monocytes from healthy controls to SLE sera also upregulated the expression of CD64 in an IFN-I-dependent manner. Decreased CD64 expression was observed concomitant with the reduction of ISG expression after high-dose corticosteroid therapy.Expression of CD64 on circulating monocytes is IFN-I inducible and highly correlated with ISG expression. Flow-cytometry analysis of CD64 expression on circulating monocytes is a convenient and rapid approach for estimating IFN-I levels in SLE patients.It has become increasingly clear that the autoantibody responses characteristic of systemic lupus erythematosus (SLE), such as anti-double-stranded (ds) DNA and anti-Sm, as well as certain clinical manifestations, notably lupus nephritis, are linked to the overproduction of type I interferon (IFN-I) [1-5]. The importance of IFN-I in autoimmunity is evident in the association between autoimmune manifestations and IFN-¦Á treatment in some patients with hepatitis C infection, malignant carcinoid syndrome, or chronic myelogenous leukemia [6-8]. A positive fluorescent antinuclear antibody test can be found in up to 22% of patients treated with IFN-¦Á [6], and the onset of SLE, autoimmune (Hashimoto) thyroiditis, autoimmune hemolytic a
%U http://arthritis-research.com/content/12/3/R90