Analysis of the phosphorylation status of early B-lineage cells from a healthy control, patient 2, and patient 3. BM cells were permeabilized and stained with FITC-labeled anti-TdT and PE-labeled phospho-PLCγ2 or total tyrosine phosphorylation. The data are shown as density plots. Quadrants were drawn based on the positive and negative TdT⁻ cells from the control. The percentage of TdT⁺ cells that was positive for the phospho-antibody is shown in the upper right corner of each plot.