Cyclic Leukocytosis in Chronic Myelogenous Leukemia: New Perspectives on Pathogenesis and Therapy

Studies were performed on a teen-age female identical twin with cyclic leukocytosis and Ph¹-positive chronic myelogenous leukemia (CML), in an attempt to analyze the relationship of these cycles to her disease and to utilize the cycles as reference points for kinetic studies and as landmarks in the progression of her disease. She remained untreated for 2½ yr. Colony-stimulating factor levels showed an inverse relationship to the peripheral leukocyte count. Two distinct phases in cyclic patterns of peripheral leukocyte counts prior to treatment could be appreciated in retrospect: phase 1, a stable 15-mo period during which leukocyte counts peaked every 10 wk and then returned to baseline levels, and phase 2, an 18-mo period of insidious deterioration during which the low points of successive cycles became progressively higher and leukocytes were accumulating in the peripheral blood at a rate of 400 x 10⁶/day. We propose that the increased marrow production of myeloid cells in this disease does not represent a life-threatening situation until cell accumulation begins. We attempted, therefore, to halt or to reverse this accumulation by cell separator leukapheresis.