The influence of amifostine used alone or in combination with 2-chlorodeoxyadenosine on normal and chronic myelogenous leukemia granulocyte-macrophage progenitor cells in vitro.

We evaluated the influence of amifostine used alone or in combination with 2-chlorodeoxyadenosine (2-CdA) on the colony growth of normal and chronic myeloid leukemia (CML) granulocyte-macrophage progenitor cells (CFU-GM) in semisolid culture in vitro. Amifostine at a concentration of 1 mg/ml was either added directly to the culture medium of normal and CML CFU-GM, or mononuclear cells (MNCs) were first preincubated with amifostine at the same concentration, washed in Iscove's modified Dulbecco minimum essential medium (IDMEM) and then added to the culture medium. Amifostine used alone inhibited the growth of CML CFU-GM colonies to a higher degree than those of normal CFU-GM, but the differences were not statistically significant. Amifostine preincubated with MNCs and used together with the highest concentration of 2-CdA significantly inhibited the colony growth of CML CFU-GM as compared to 2-CdA alone (p<0.05). In contrast, the colony growth inhibition of normal CFU-GM was not significantly lower compared to 2-CdA used alone. Our studies suggest that 2-CdA used together with amifostine is more toxic to leukemic CFU-GM than to their normal counterparts.