Leukemic host influence on normal erythrocytic and granulocytic colony formation in in vivo plasma clot diffusion...

The effect of a leukemic environment on normal erythroid and granulocytic colony formation was examined in in vivo plasma clot diffusion chamber cultures implanted into Shay chloroleukemic rat hosts at varying stages of the disease. Normal bone marrow cells isolated in plasma clot diffusion chamber cultures in leukemic hosts displayed significant differences in the pattern of normal bone marrow colony growth. Granulocyte colony-forming units were significantly inhibited by leukemic hosts throughout the course of the disease. The size of developing colonies was reduced to under 100 cells; however, maturation within these clusters appeared unaffected. Erythroid colonies showed a slight inhibition during the early stages of the leukemia, a significant stimulation of 100 to 350% in the midleukemic period, and a significant inhibition of 50 to 65% during the terminal stages of the disease. Burst formation was also inhibited in the late leukemic stages. The transient increase in erythroid colony-forming units on Days 7 and 8 of the leukemia was concomitant with the onset of the anemia associated with the disease. Since the normal bone marrow cells were compartmentalized within the plasma clot diffusion chamber cultures, the suppression of erythroid and granulocytic colony development appears to be directly due to the release of diffusible inhibitory substances from the leukemic animal.