TO THE INCIDENCE OF NUCLEOLI IN CIRCULATING MYELOBLASTS OF PATIENTS SUFFERING FROM ACUTE MYELOBLASTIC, PROMYELOCYTIC AND MYELOMONOCYTIC LEUKEMIAS

: Nucleoli were studied in circulating myeloblasts of myeloblastic (FAB M1, M2), promyelocytic (FAB M3) and myelomonocytic (FAB M4) acute myeloid leukemias (AMLs) using a cytochemical procedure for the demonstration of RNA. In patients untreated with cytostatic chemotherapy, myeloblasts of myeloblastic acute leukemias possessed less frequently "active large" nucleoli and more frequently "inactive" micronucleoli in comparison with other investigated types of AMLs. When myeloblasts were classified according to the presence of functionally dominant nucleoli, the higher percentage of "terminal" myeloblasts containing only micronucleoli in this type of AML was significantly reduced in patients treated with the cytostatic chemotherapy. In patients suffering from promyelocytic leukemia treated with cytostatic chemotherapy, the decreased percentage of myeloblasts containing functionally dominant active large nucleoli was accompanied by the increased incidence of myeloblasts with functionally dominant "resting" ring shaped nucleoli. In myelomonocytic AML no significant differences were noted between patients untreated or treated with the cytostatic chemotherapy in the incidence of main nucleolar types in myeloblasts and myeloblasts classified according to the presence of functionally dominant nucleoli. Thus a further biological specificity might exist among leukemic blasts in various types of AMLs which should be considered for a rational approach to the therapy of these malignancies. In addition, the cytostatic chemotherapy did not influence incidence of the nucleolar asynchrony in myeloblasts of all investigated types of AML.