SAT0002 Quantitative CD64 Molecules on Peripheral Blood Monocytes in Systemic Lupus Erythematosus (SLE)

Background The majority of SLE patients show evidence of excess type I interferon (IFN-I) production, a phenotype associated with renal disease and certain autoantibodies. However, detection of IFN-I proteins in serum is expensive examination and time consuming. Research in the past few years has demonstrated that their relative expression on circulating monocytes/macrophages may be modified by cytokines, including interferon (IFN)-α1. Little data exist on the in vivo expression of specific FcγRI, CD64 in SLE. However, the quantitative expression of CD64 on monocytes has not been reported. For the treatment early intervention, more rapid disease activity assessment is required in SLE. Objectives To determine whether quantitative expression of CD64 on circulating monocytes (mCD64) is associated with systemic exacerbation in SLE patients. Methods In this study, 10 SLE patients with high disease activity (aSLE), 20 SLE patients with quiescent activity (qSLE) and 20 healthy controls (HC) were enrolled. We measured the expression level of CD64 per monocyte quantitatively by flow cytometry. Comparisons of levels within each group were analyzed, and levels of respective measurements at both pre- and post-treatment in aSLE were analyzed. The expression level of mCD64 was compared with SLE disease activity index (SLEDAI) and SLE disease activity biomarkers (anti DNA antibody and compliments titer). Results aSLE had a mean SLEDAI of 12.1±7, and qSLE SLEDAI was 3.0±1.6. In aSLE and qSLE, mean expression level of mCD64 was 39800±16609 and 21759±7423 molecules/cell (p