Lentiviral barcoding of primary pediatric leukemia. (A) Experimental design. (B) Gating strategy for flow cytometric detection of human leukemia cells in mouse blood. FSC, forward scatter; SSC, side scatter. (C-E) Percentage of human chimerism (%hCD45⁺ of live cells) in blood of serial xenografts of patient-derived leukemia. Connected dots represent samples from a single mouse. (F-H) Survival of serial xenografts of patient-derived leukemia. Each dot represents a single mouse. (I-J) Spleen size in control and leukemic mice. Each dot is 1 mouse. ***P < .001.