EXPRESSION OF INTERLEUKIN-1, INTERLEUKIN-3, INTERLEUKIN-6, STEM-CELL FACTOR AND THEIR RECEPTORS IN ACUTE-LEUKEMIA BLAST CELLS AND IN NORMAL PERIPHERAL LYMPHOCYTES AND MONOCYTES

Reverse transcriptase-polymerase chain reaction amplification (RT-PCR) and Southern blot analysis were used to evaluate ligand and receptor expression of interleukin 1alpha (IL-1alpha), interleukin 3 (IL-3), interleukin 6 (IL-6) and stem cell factor (SCF) in peripheral blood lymphocytes and monocytes and in several acute leukemia blast cell populations. Resting peripheral lymphocytes and monocytes expressed both ligand and receptor of the four cytokines at considerable levels. The leukemic blast cells of the M1-M4 phenotypes are characterized by almost complete lack of expression of IL-1alpha, IL-3 and IL-6 and the constant and usually high expression of SCF. On the other hand, these myeloid blast cells express generally high levels of the four cytokine receptors. The data suggest that the regulation of the expression of IL-1alpha, IL-3 and IL-6, at least in our limited number of leukemic cell populations studied, is independent of that of SCF. The results indicate that, at least in most of the leukemic myeloid blasts cells, the expression of SCF and its receptor, the c-kit oncogene, may permit an autocrine regulation of cell cycling.