A myelosclerotic syndrome in mice engrafted with cells producing high levels of leukemia inhibitory factor (LIF).

DBA/2 mice engrafted with FDC-P1 cells producing high levels of the leukemia-inhibitory factor (LIF) developed high circulating levels of LIF and a fatal syndrome including the accumulation of excess osteoblasts in the marrow and new bone formation. The mice developed a neutrophil leucocytosis, an enlarged spleen, and excess numbers of hemopoietic cells in the spleen and liver. Marrow cellularity was reduced with selective survival of granulocytic cells, but the frequency of hemopoietic progenitor cells in both the marrow and spleen was higher than in control mice. Megakaryocyte numbers were reduced in marrows with pronounced sclerosis. The disease state may represent a useful model of myelosclerosis, but it remains to be established whether the hemopoietic abnormalities in these mice are direct effects of LIF or secondary changes following occlusion of the marrow by osteosclerotic tissue.