Engraftment of NOD/SCID-IL2Ry-chain knockout (NSG) mice with CD34⁺ BM cells from CML patients treated with imatinib mesylate. (A) The schematic for these experiments is shown. BM CD34⁺ cells from CML patients in remission (n = 6) were transplanted via tail vein injection into sublethally irradiated NSG mice (3-4 mice per sample, total of 20 mice). Mice were evaluated for human cell engraftment and BCR-ABL status of engrafted cells after 11-12 weeks. (B) The percentage of human CD45⁺ cell engraftment in BM, spleen and PB of mice transplanted with CD34⁺ cells are shown. Results represent the mean ± SEM of human CD45⁺ cells engrafted in BM, spleen, and PB for each BM sample transplanted. (C) The percentage of human CD45⁺ cells expressing different surface markers in mouse BM, spleen, and PB are shown (n = 20). (D) The BCR-ABL status of engrafted cells was evaluated using Q-PCR. BCR-ABL expression in human cells engrafted in BM of individual mice is shown (n = 15). Horizontal bars represent median values. Samples from the 5 mice that were excluded also expressed BCR-ABL, but BCR values were too low to allow quantitation.