Flow cytometry reveals 2 populations of lymphocytes and monocytes in the female patient.

PBMCs were stained intracellularly with WASP mAb 5A5. Lymphocytes and monocytes were gated on forward and side scatter. Note the presence of 2 populations, WASP^bright and WASP^dim, for both lymphocytes and monocytes of the patient. Lymphocytes of her mother are all WASP^bright; the mother's monocytes are primarily WASP^bright with a small WASP^dim population. For the patient's cousin (IV-22) and grandmother (III-4), who are both carriers, all lymphocytes and monocytes were WASP^bright. Open histograms indicate isotype control; closed histograms, WASP staining.