In vitro growth of myeloid and erythroid progenitor cells from myelodysplastic patients in response to recombinant human granulocyte-macrophage colony-stimulating factor.

Marrow progenitor cells from 14 myelodysplastic (MDS) patients and 17 normal donors were assayed in semisolid cultures supplemented with increasing doses of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) or medium conditioned by 5637 bladder carcinoma cells (5637CM). At doses of supplements shown to be optimal for colony formation in cultures of normal marrow, myeloid (day 14) colony numbers were subnormal in 10 of 14 MDS marrows cultured in 5637CM and in 8 of 14 cultures containing rhGM-CSF (2.5 ng/ml). However, a high dose of rhGM-CSF (20 ng/ml) raised myeloid colony numbers in cultures of many MDS marrows, so that 9 of 14 now yielded colonies within the normal range; increased levels of 5637CM failed to do this. Erythroid colony growth was poor in 13 of 14 MDS marrow cultures supplemented with erythropoietin in addition to 5637CM or rhGM-CSF. High concentrations of rhGM-CSF did not increase erythroid growth. These data suggest that myeloid progenitors from the MDS clone may have a decreased responsiveness to hemopoietins which can be overcome at high concentrations of growth factors.