Interleukin-10 inhibits the autocrine growth of leukemic blast cells from patients with acute myeloblastic leukemia

The effect of interleukin-10 (IL-10) on the growth of leukemic blast cells from patients with acute myeloblastic leukemia (AML) is in need of clarification. We therefore examined the effect of IL-10 on AML cells obtained from 10 patients. Although granulocyte colony-stimulating factor (G-CSF) and/or granulocyte/macrophage colony-stimulating factor (GM-CSF) was able to stimulate the growth of AML progenitor cells to form leukemic blast colonies, IL-10 itself demonstrated no leukemic blast colony-forming activity and no synergistic stimulating activity with other cytokines. However, leukemic blast colonies were formed without the addition of exogenous cytokines in four cases and IL-10 suppressed these spontaneous colony formations in two of the four cases. Since the production of G-CSF and GM-CSF was observed in these two cases, the presence of an autocrine growth mechanism mediated by these cytokines was suggested. When serial concentrations of IL-10 were added, the production of G-CSF and GM-CSF was dramatically inhibited in a dose-dependent manner. These findings suggested that IL-10 could suppress the autocrine growth of AML cells by inhibiting their production of G-CSF and/or GM-CSF. In addition, the administration of IL-10 may be harmless to normal hematopoiesis because IL-10 did not suppress the growth of normal hematopoietic progenitor cells. Our study provides experimental support for the clinical application of IL-10 in patients with AML. (C) 1997 Elsevier Science Ireland Ltd.