B-cell aplasia in the peripheral blood and BM of patient ALL-1 after infusion with autologous 19-28z⁺ T cells. Samples before and after infusion of blood (A) and BM (B) were obtained at the time points indicated on the x-axis and used for cell counts and immunophenotyping. Cell concentrations were measured with an AcT diff cell counter (Coulter). Immunophenotyping was performed by gating on CD45 and defining cell populations with the following cell surface markers: CD3⁺ (T cells), CD19⁺CD10⁻ (mature B cells), CD19⁺CD10⁺ (progenitor B cells or tumor cells), CD19⁻CD10⁺ (granulocytes). (A) The plotted value for each cell population was derived as the product of the cell concentration by the frequency. (B) The plotted value for each cell population represents the percentage within the CD45 gate.