Comparing CD200 expression in low-risk and risk ALL. (A) Cells from 25 MRD low-risk ALL patients (1-3, 5, 6, 8, 14, 23, 25, 30-32, 34-43, 51, 59) (panel Ai) and 17 risk ALL patients (9, 12, 13, 22, 24, 27-29, 33, 44-50, 60) (panel Aii) were stained for CD34 and CD19 and gated into CD34⁺/CD19⁺, CD34⁺/CD19^–, CD34^–/CD19⁺ and CD34^–/CD19^– populations; the proportion of CD200 was then determined. Each symbol represents a different patient, and horizontal lines represent the median. (B) In a subset of patients with 5 MRD low-risk patients (34, 42, 43, 51, 59) and 8 MRD risk patients (28, 33, 44-47, 50, 60), both CD200 expression (Bi) and number of binding sites (Bii) were calculated. Bars represent median expression, and error bars represent the interquartile range.