LSC populations from paired AML diagnosis and relapse samples. (A) Engraftment levels of sorted cells of 4 populations (CD34⁺CD38⁻, CD34⁺CD38⁺, CD34⁻CD38⁺, CD34⁻CD38⁻), as well as unsorted cells from a representative AML sample (AML3) at diagnosis and relapse. Each dot represents the human CD45⁺ engraftment level in BM of individual NSG mouse; a percentage greater than 0.1 is defined as leukemic engraftment. The horizontal line is the mean level of engraftment for each population. (B) Summary of the LSC activity in 7 sorted AML samples (as defined by CD34 and CD38 or CD32 and CD38) at diagnosis and relapse. The equivalent dose of mononuclear cells per mouse is from 5 × 10⁵ to 3 × 10⁶ cells for sorted populations. The summary of cell dose for primary xenotransplantation is in supplemental Table 3. Plus sign indicates LSC detected at this sensitivity; minus sign indicates no LSC detected at this sensitivity. *LSC activity detected using NOD-scid IL2Rgnull-3/GM/SF mice because of limited materials.