THE EFFECT OF HUMAN FLT-3 LIGAND ON COMMITTED PROGENITOR-CELL PRODUCTION FROM NORMAL, APLASTIC-ANEMIA AND DIAMOND-BLACKFAN ANEMIA BONE-MARROW

We investigated the effect of the human ligand for flt-3 (FL) on the c ommitted progenitor colony formation of normal bone marrow (BM) (n = 9 ) and BM from four aplastic anaemia (AA) and three Diamond-Blackfan an aemia (DBA) patients. Methylcellulose committed progenitor cell assays were carried out using FL, alone and in combinations with granulocyte -macrophage colony-stimulating factor (GMCSF), interleukin-3 (IL-3) an d c-kit ligand (KL). FL alone had a limited, though significant, effec t on the production of granulocyte-macrophage colony-forming unit (CFU -GM) colonies from normal BM and showed an additive effect with IL-3 a nd GMCSF separately, but not in combination. FL did not increase the s timulation of KL and did not have an effect on the production of eryth roid progenitor colonies, FL had no effect on the AA and DBA BMs studi ed.