Effect of SDF-1 addition on G-CSF induced differentiation of 32D/G-CSF-R cells. Differential counts after 7, 9, and 12 days of culture in the presence of G-CSF (-) or G-CSF + SDF-1 (+ SDF). □ indicates the percentage of terminally matured neutrophils; ▦, the percentage of intermediately matured granulocytic cells; and ▪, the percentages of blast cells in the cultures.