Proliferative activity of bone marrow cells in primary dysmyelopoietic (preleukemic) syndromes.

The proliferative activity of bone marrow cells was studied in 24 patients with primary dysmyelopoiesis by means of flow cytometry and 3H-TdR autoradiography. Abnormal DNA content was found in two cases with aneuploid karyotypes. DNA content typical of a diploid population was observed in all patients with normal karyotype and in three patients with chromosomal aberrations. The fraction of bone marrow cells in S- and G2-phase was higher in primary acquired sideroblastic anemia and refractory anemia (without excess of blasts) than in refractory anemia with excess of blasts and chronic myelomonocytic leukemia. Regardless to the diagnosis, the patients with low fraction of cells in S- and G2-phase had short survival time and showed high rate of evolution into acute nonlymphoblastic leukemia. The labeling (LI) and mitotic (MI) indexes of both erythroblasts and granulocytic cells were decreased in nearly all patients. The lowest values of LI and MI of the granulocytic compartment were found in the patients who subsequently developed acute leukemia. These data suggest that cytokinetic analysis allows investigators to achieve useful information on the stage of disease in the dysmyelopoietic syndromes.