CD34⁺/CD86⁺ cells cultured in G-CSF do not generate granulocytes. Human marrow CD34⁺/CD86⁺ and CD34⁺/CD86⁻ cells were purified by FACS-sorting and cultured for 9 to 11 days in G-CSF. Cultured cells were stained and analyzed by microfluorimetry.