Abstract: | We investigated the responsiveness of granulocyte-committed progenitors (CFU-G/D) from patients with chronic myeloid leukemia (CML) and healthy subjects to stimulating and inhibiting activities released by murine macrophages in diffusion chamber culture. CFU-G/D from CML demonstrate a normal response to macrophage-derived stimulation. The responsiveness of CFU-G/D from patients with CML to indomethacin-sensitive inhibition was significantly suppressed. In this regard no difference between CFU-G/D from bone marrow and blood of patients with CML could be observed. Colonies formed both by CFU-G/D from healthy subjects and CML consisted exclusively of cells of granulocyte line: from myeloblasts up to polymorphonuclear granulocytes. Similar cellular composition of colonies could be noted during macrophage-derived stimulation and inhibition of CFU-G/D growth. In conclusion, we have demonstrated that CML CFU-G/D which proliferate and differentiate in diffusion chamber culture show a normal response to macrophage-derived stimulation but are less sensitive to indomethacin-dependent inhibition. |