The effect of human and rat fetal bone on hematopoiesis in vitro and in vivo.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a regulatory, glycoprotein necessary for the proliferation, maturation, and survival of myeloid cells [4]. Myelopoiesis is enhanced when recombinant human (rh) GM-CSF is given to mice, monkeys [6], and some patients with various forms of neutropenia [3, 5]. The clinical use of rhGM-CSF infusions is under intensive investigation now. An alternative way of increasing the level of GM-CSF in the organism is by transplantation of CSF -producing cells, analogous to the transplantation of insulin-producing cells in patients with diabetes mellitus. It seems especially important to increase the intramedullary concentration of GM-CSF, as bone marrow is the central organ for regulating the proliferation and differentiation of hematopoietic cells. There is a positive correlation between the intramedullary concentration of GM-CSF and the prognosis for patients with leukemia [8]. One source of CSF-producing cells may be various embryonal cells which are available and genetically more tolerable. The main objectives of this study were: (a) to evaluate the ability of various human fetal organs and tissues to develop colony-stimulating and -inhibiting activities (CSA and CIA); (b) to estimate their effect on colony-forming unit-granulocyte macrophage (FU-GM) and leukemic clonogenic cells (LCC); (c) to evaluate the effect of fetal bone (FB) on fibrous tissue of adult bone marrow in