GATA2 is required for NK cell differentiation from CD34⁺ precursors. Highly purified CD34⁺ hematopoietic precursors from GATA2-deficient patient 3 or a healthy donor were isolated from peripheral blood by FACS and cultured on EL08.1D2 stromal cells in the presence of IL-3, IL-6, IL-7, stem cell factor, Flt3L, and IL-15. After 30 days, cells were isolated and (A) expansion was calculated based on cell number recovered for control (black) and patient (white). (B) Patient cells (black) and control cells (red) were analyzed for CD56 expression. Control cells were 2.3% CD56^bright. Isotype control staining is shown in gray. (C) CD56 on (left) control cells or (right) patient cells was analyzed in combination with pan-KIR antibody (bottom).