In vivo repopulating capacity and phenotypic analysis of engrafted NOD/SCID BM. ALL cells from 10 patients (1, 2, 5-11, 14) were sorted for expression of CD133 and CD19. Both unsorted cells and the sorted subfractions were evaluated for their ability to engraft irradiated NOD/SCID recipients (A). Each patient is represented by a specific symbol, and each symbol depicts the engraftment as measured by CD45⁺ cells present in the BM of the NOD/SCID recipients. BM cells removed from NOD/SCID mice that had been engrafted with CD133⁺/CD19⁻ cells were analyzed in more detail using additional lineage markers (B). Cells were initially gated on the basis of low forward and side scatter; then CD45⁺ cells were gated and the expression of the lymphoid and myeloid antigens on these gated cells was investigated. The peaks representing CD3 and CD33 antibodies are shown in black, and isotype controls are represented as translucent peaks on the overlay histograms. The figure shows the immunophenotype of cells removed from an NOD/SCID mouse inoculated with CD133⁺/CD19⁻ cells from patient 14.