Increased lymphocyte apoptosis with upregulation of CD200 expression in systemic lupus erythematosus. (A) Percentage of spontaneous early apoptotic lymphocytes (annexin V+PI-) in peripheral blood mononuclear cells from systemic lupus erythematosus (SLE) patients (n = 30) was significantly higher than in healthy controls (HCs) (n = 15) (median 6.80, interquartile range 4.38 to 11.23 vs. 4.50, 3.50 to 5.30; P = 0.027). (B) CD200 relative expression ratio, defined as the percentage of CD200 positivity on early apoptotic cells to live cells, was significantly increased in SLE patients compared with HCs (median 2.83, interquartile range 1.50 to 6.04 vs. 1.64, 1.38 to 2.42; P = 0.037). PI, propidium iodide.
Li et al. Arthritis Research & Therapy 2012 14:R123 doi:10.1186/ar3853