Figure 1

CD200 and CD200 receptor 1 expression in systemic lupus erythematosus patients and healthy controls. (A) CD200 expression in peripheral blood mononuclear cells (PBMC) was upregulated in systemic lupus erythematosus (SLE) patients. Open histogram: percentage of CD200⁺ cells in PBMC; gray histogram, IgG control. (B) Percentage of CD200⁺ cells in PBMC (12.03 ± 9.67% vs. 6.68 ± 2.69%, P = 0.026), CD4⁺ T cells (9.17 ± 3.26% vs. 6.45 ± 2.82%, P = 0.012), CD14⁺ monocytes, CD11c^-CD123^high plasmacytoid dendritic cells (pDCs) (15.57 ± 10.48% vs. 7.89 ± 4.26%, P = 0.004) and CD11c⁺CD123^- myeloid dendritic cells (mDCs) (6.55 ± 3.46% vs. 4.01 ± 2.10%, P = 0.016) from SLE patients (n = 53) and healthy controls (HCs) (n = 24). (C) CD200 receptor 1 (CD200R1) expression in PBMC was downregulated in SLE patients. Open histogram: percentage of CD200R1⁺ cells in PBMC; gray histogram, IgG control. (D) Percentage of CD200R1⁺ cells in PBMC (3.10 ± 2.24% vs.6.88 ± 3.61%, P = 0.001), CD4⁺ T cells (10.11 ± 7.37% vs. 15.08 ± 7.50%, P = 0.004), CD14⁺ monocytes, CD11c^-CD123^high pDCs (45.93 ± 24.07% vs. 71.28 ± 13.91%, P < 0.001) and CD11c⁺CD123^- mDCs (18.91 ± 14.90% vs. 34.75 ± 16.82%, P < 0.001) from SLE patients (n = 53) and HCs (n = 24). (E) mRNA expression of both CD200 (median 0.44, interquartile range 0.20 to 1.02 vs. 1.67, 0.93 to 2.80; P < 0.001) and CD200R1 (median 1.45, interquartile range 0.85 to 3.42 vs. 4.69, 2.33 to 6.33; P < 0.001) in PBMC was significantly lower in SLE patients than in HCs.