Relation of leukemic blast cell dye efflux and maximum CMA-676 saturation of CD33 sites on peripheral blood blast-sized cells with treatment response (N = 36). (▴) Denotes patients who had <5% leukemic blasts by morphologic examination of bone marrow aspirate and biopsy specimens after treatment. (•) Denotes patients whose leukemia did not disappear. Peripheral blood samples from four patients were unavailable for analysis. The efflux from the dominant population is represented in the five instances in which efflux profiles were bimodal. *Leukemic cell specimens from patients FH-023 and FH-024 were 2 and 3 days old, respectively, at the time of efflux measurement. Because blast-sized cells from each showed uncharacteristically low DiOC₂ loading, obtained efflux values may underestimate true efflux.