Flow cytometric detection of human cells in the bone marrow of NOD/SCID β2M null mice that received transplants with Lin^-, ALDH^loLin^-, or ALDH^hiLin^- cells. Representative flow cytometric analysis of NOD/SCID β2M null mice that received transplants with (A-C) 1 × 10⁵ Lin^-, (D-F) 4 × 10⁵ ALDH^loLin^-,or (G-I) 1 × 10⁴ ALDH^hiLin^- cells. Mouse BM, spleen, and peripheral blood were extracted 7 to 8 weeks after transplantation, and human cells were detected by coexpression of the pan-leukocyte marker CD45 (R1) with CD38 (R2) in mice injected with ALDH^hiLin^- cells. Representative mice showed 18.0% human CD45⁺CD38⁺ cells after the transplantation of 10⁵ Lin^- cells and 16.5% human CD45⁺CD38⁺ cells after the transplantation of 10⁴ ALDH^hiLin^- cells. Human cells were not detected in mice that received transplants with 4 × 10⁵ ALDH^loLin^- cells.