Mitotic Activity in Myeloid Leukaemias

Abstract

The proportions of myeloblasts, promyelocytes, myelocytes and promonocytes within the granulopoietic precursor pool of the bone marrow and mitotic indices (MI) of the precursor cells were determined in 277 patients with various forms of myeloid leukemias. The MI of the leukemic patients were significantly lower than those of 20 normals. The median MI in 186 cases of acute myeloid leukemias was 0.68%, compared with 1.0% in 85 cases of chronic leukemias and 1.2% in the normals. Separate MI of the different leukemic precursor cells were counted in 21 cases of acute myeloid leukemias and these indices were lower than those of the corresponding normal cells. There were significant differences between the different groups and subtypes of leukemias. Mitotic countings might be of diagnostic and prognostic significance.