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

Single CD34⁺CD38⁻ cells from 5 MDS cases with trisomy 8 were plated in 3 different cytokine combinations (SF = SCF + FL, SFM = SCF + FL + MGDF and Cocktail = SCF + FL + MGDF + IL-3 + G-CSF + GM-CSF + EPO) as described in “Patients, materials, and methods.” Also shown (to the left) are results from identical experiments with CD34⁺CD38⁻ cells from 8 healthy subjects (error bars show SEM). Wells were scored for total clones per 120 wells and for size (3-50 cells or more than 50 cells) after 11-13 days of incubation. No clones were observed for patients #6 and #11 when stimulated only with SCF + FL. In general, clones from all MDS patients were too small to be analyzed by FISH.