FACS analysis of Flt3 labeling of unfractionated marrow mononuclear cells and purified CD34⁺ cells. (A) Expression of Flt3 receptor versus CD14 on unfractionated marrow mononuclear cells. Cells were first gated to exclude dead cells (not shown). Quadrants were drawn as shown in (B). In the results of immunostaining of purified CD34⁺ cells, expression of Flt3 receptor was correlated with (C) CD38, or (D) CD117 (kit). For (C) and (D), a CD34⁺ cell gate had been set first (not shown). (E) A blast gate was set (not shown), then a gate was set on the brightest Flt3⁺ cells (R1). Expression of CD14 and CD64 on CD34⁺ cells gated on R1 (F). The results shown are representative of two (A) or three (B to F) experiments.