Responsiveness of CD34⁺CD38⁻MDS cells to early-acting cytokines.

CD34⁺CD38⁻ cells were plated at the single-cell level as described in “Materials and methods” and cultured in 3 different cytokine combinations: a = SCF + FL; b = SCF + FL + MGDF; and c = cocktail (SCF + FL + MGDF + IL-3 + G-CSF + GM-CSF + Epo). Five normal subjects were used as controls. Wells were scored for total clones per 120 wells and for size (3-50 cells and more than 50 cells) after 11 to 13 days of incubation. No clones were observed for MDS patients 7 and 8 in response to cytokine combination “a.” In general, the clones formed from CD34⁺CD38⁻cells were too small to allow FISH analysis.