Clonal chromosomal evolution was observed in a 16-year-old boy suffering from Ph1-positive CML. An isodicentric Ph1 chromosome appeared 20 weeks after the initial diagnosis. At that time an allogeneic bone marrow transplantation was performed. Thereafter, during an observation period of more than 13 months, chromosome analyses showed neither the Ph1 chromosome nor the abnormal isodicentric variant. Close cytogenetic monitoring is suggested to reveal early unfavorable prognostic signs of the onset of blast crisis before it becomes evident in the bone marrow morphology.
A patient with chronic myelocytic leukemia had a cyclic oscillation of blood neutrophils, eosinophils, monocytes, platelets, normoblasts, and reticulocytes but not of lymphocytes. The cycle interval was 53--69 days. Except for reticulocytes all other cells cycled with neutrophils. Plasma colony-stimulating factor (CSF) oscillated out of phase with neutrophils, suggesting that granulocytopoiesis is regulated through CSF by a feed-back mechanism. Plasma erythropoiesis-stimulating factor (ESF) also oscillated. ESF crests preceded or coincided with reticulocyte crests, indicating that the ESF elevation may have been responsible for the reticulocyte peaks. The relationship between neutrophils and reticulocytes and their oscillations with plasma CSF and ESF suggests that there is a common stem cell which differentiates along one cell line or the other depending upon the balance of regulatory stimuli. The fraction of blood neutrophilic precursors (myeloblasts, promyelocytes, and myelocytes) in DNA synthesis fluctuated with neutrophil level. The calculated generation time was shorter at the crests than at the troughs of the neutrophil cycles. This finding suggested that the rate of proliferation of the neutrophils changed periodically. This observation, along with a periodic increase in differentiation of the stem cell toward the neutrophilic cells, is the probable explanation of oscillation of the neutrophil count in the blood.
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