CD4 and acute lymphoblastic leukemia: The highest levels of cell surface CXCR3 were found in leukemic cells (GFP+/CD4+CD8+DP) colonizing the meninges, thymus, and BM, as opposed to the liver, spleen, lungs, and blood in ΔE NOTCH1 T-ALL mice (Figure 1G and Supplemental Figure 1I).