Figure 1

CD64 expression on monocytes is increased in SLE. (a) Flow-cytometry analysis of monocyte markers in SLE patients (n = 108) and healthy controls (n = 83). Bars represent the average mean fluorescent intensity on CD14⁺ monocytes, and error bars denote standard error. *P < 0.05; **P < 0.01; ***P < 0.001. (b) Representative flow cytometry of CD64 expression on peripheral blood cells from a lupus patient, including CD3⁺ T cells, CD19⁺ B cells, CD14⁺ monocytes, CD16⁺ neutrophils, and CD11c⁺ dendritic cells (primarily myeloid dendritic cells). Lymphocytes, monocytes, and neutrophils were gated based on their forward/sideward scatter characteristics. Dendritic cells were first gated on Lin^-, HLA-DR⁺ cells, and then further identified as myeloid dendritic cells (CD123^-, CD11c⁺) with flow cytometry. (c) Bivariate analysis of CD64 expression on monocytes (MFI, determined with flow cytometry) and SLEDAI (n = 108). Correlation coefficient was calculated by using Spearman's rank correlation (P = 0.0017; r = 0.301).