Prognostic value of mitotic studies in myeloid leukaemias

In vitro colony and cluster growth in haemopoietic dysplasia (the preleukaemic syndrome). II. Identification of a maturation defect in agar cultures

The growth and differentiation of granulopoietic progenitor cells from 15 patients with haemopoietic dysplasia were studied by in vitro culture in agar-gel. After 14 d in culture whole colonies and clusters were transferred to glass slides and were stained with a modified Papanicolaou technique. The preparations were examined for cellular differentiation by counting the number of mature cells (band forms and polymorphonuclear cells) and a mitotic index was calculated from the number of mitotic cells. Patients with defective colony formation showed granulopoietic maturation defects and a reduced mitotic index was found in some colonies. Patients who had colony counts within the normal range, however, showed normal in vitro maturation. Defective colony growth in haemopoietic dysplasia generally indicates a malignant course and can occasionally be related to leukaemic transformation. The finding of in vitro maturation defects in an additional culture abnormality which may indicate a deteriorating clinical course. A defective maturation and a reduced mitotic index in vitro add support to the concept of clonal progression in malignant haemopoietic dysplasia.

Mitotic activity in myeloid leukaemias. A study of 277 cases

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 leukaemias. The MI of the leukaemic patients were significantly lower than those of 20 normals. Thus the median MI in 186 cases of acute myeloid leukaemias was 0.68%, compared with 1.0% in 85 cases of chronic leukaemias and 1.2% in the normals. Separate MI of the different leukaemic precursor cells were counted in 21 cases of acute myeloid leukaemias and these indices were lower than those of the corresponding normal cells. There were significant differences between the different groups and subtypes of leukaemias and it is suggested that mitotic countings might be of diagnostic and prognostic significance.

Mitotic activity of the granulopoietic precursor cells in the peripheral blood in chronic myeloid leukaemia

The mitotic indices (MI) of granulopoietic precursor cells in peripheral blood and bone marrow were studied in 38 patients with typical chronic myeloid leukaemia (CML) in the chronic phase. The MI in the peripheral blood were very low, in the median 0.07%, compared to those in the bone marrow with a median of 1.07%. The blood MI were significantly increasing with raising WCC and the values of the MI above the median were combined with short survival times. The bone marrow MI were negatively correlated to the blood MI and it is suggested that this is a sign of an increased exchange of cells between bone marrow and blood.