Phenotypic evaluation of chronic myeloid leukemia.

Marrow culture studies revealed a spectrum of qualitative and quantitative defects in granulocyte-macrophage progenitors (GM-CFC) of patients with chronic myeloid leukemia in chronic phase and blastic crisis. Parallel culture studies and terminal transferase determinations revealed that a significant proportion of patients in blastic crisis possess two coexisting acute phase clones, one lymphoblastic and one myeloblastic. Measurement of response to and production of T cell growth factor showed that the leukemic blast cells from patients with TdT-positive blastic crisis produced the factor, but did not exhibit a proliferative response to exogenous factor. This phenotype was identical to that observed in TdT-positive acute lymphoblastic leukemia. Additional regulatory defects were identified in CML, since leukemic GM-CFC proliferation was resistant to inhibition by concentrations of prostaglandin E, which are markedly inhibitory for normal GM-CFC. The self-renewal or recloning capacity of GM-CFC was also identified as a unique feature of some patients with CML. The addition of retinoic acid to primary cultures of leukemic GM-CFC completely abolished this recloning capacity.