Engraftment of primary childhood ALL cells from patients 1 through 8.

Mice were irradiated and inoculated with mononuclear cells from bone marrow biopsies. At weekly intervals the proportion of human CD45⁺ cells in the murine peripheral blood was estimated by multiparameter flow cytometry, as described in “Patients and methods.” Experiments were terminated at the first indication of morbidity, or at 25 weeks after inoculation. Numbers refer to patients (Table 1); 6d and 6r indicate patient 6 at diagnosis and relapse, respectively. All patient samples showed evidence of engraftment in the murine peripheral blood. The engraftment characteristics shown in this figure are representative of the entire cohort of 20 patient samples.