RELATIONSHIP BETWEEN RESPONSIVENESS TO COLONY-STIMULATING FACTORS (CSFS) AND SURFACE PHENOTYPE OF LEUKEMIC BLASTS

We examined the responsiveness of leukemic cells to colony stimulating factors (CSFs) as determined by 3H-TdR incorporation and surface phenotypes of leukemic blasts. In acute myeloid leukemia (AML), CD13 and/or CD33 positive and HLA-DR negative M1 and M3 cases tended to show high response to G-CSF, GM-CSFs and IL-3, however, all HLA-DR positive M1, M2, M4 and M5 cases were unresponsive to CSFs but showed high autonomous growth. In acute lymphocytic leukemia (ALL), no response was observed to any CSFs but high autonomous growth was found in mixed leukemia cases. Sole T or B lineage cases showed low autonomous growth. These results suggest the varied nature of the proliferative state in leukemia and the existence of a subgroup in M1.