Quantitation of bone marrow engraftment of JMML cells in SCID/NOD mice based on Southern blotting. (A) Bone marrow engraftment of human-derived cells in nontransplanted mice (control) and untreated, transplanted mice 2, 4, and 6 weeks posttransplant. * P < .05, ** P < .01 compared with control mice. (B) Bone marrow engraftment of human-derived cells in mice treated for 4 weeks with E21R alone and/or MoAb cA2 starting from the time of transplant (early treatment) or starting 4 weeks posttransplant (late treatment). # P < .05, ## P < .01 compared with untreated mice 4 weeks posttransplant. Values are the means + SEM from five mice.