A short note on the nuclear diameter in human early granulocytic progenitors

The information on the nuclear size in early granulocytic progenitors is very limited. Numerical data on the nuclear diameter and size in these cells are missing in the literature. Therefore the nuclei of myeloblasts and promyelocytic cells were measured in bone marrow smears of patients suffering from chronic phase of chronic myeloid leukaemia since the general morphology of granulocytic progenitors is very similar to those in non-leukemic persons. Moreover, the increased granulopoiesisinthese patients provided a satisfactory number of early granulocytic progenitors for karyometric measurements. Nuclear diameter in digitised and processed images of these cells was measured directly on the monitor screen at magnification 4300x using a computerised photoprogram. The nuclear mean diameter in both myeloblasts and promyelocytes ranged between 11 and 13 microm. Cells with smaller or larger nuclei were observed less frequently. Since the nuclear size depends on the cell cycle stage, a possibility exists that both granulocytic progenitors are mostly in the S and less frequently in G1 or G2 phase. Thus, the mean nuclear diameter, i.e. nuclear size, might be useful in helping to estimate the cell cycle stage of these cells in bone marrow smears at the single cell level. In addition, the results of the present study also indicated that the nuclear diameter in myeloblasts as well as promyelocytes of studied patients was not substantially influenced by the cytostatic therapy with imatinib mesylate.