[Incidence of internal carotid artery thrombosis and disseminated intravascular coagulopathy in the early stages of acute myeloid leukemia]

The case history of a 15 year old boy in whom thrombosis of the internal carotid artery was associated with severe disseminated intravascular thrombosis (DIC) is described. Both peripheral blood smear and bone marrow aspirate revealed acute myelogenous leukemia FAB M-2 type as the cause of the disease. Consumption coagulopathy is common sign of hemostasis disturbances in leukemia. It is frequently observed in acute promyelocytic leukemia, but rarely it may be seen in the other forms of hemoblastosis, too.

Morphologic and flow cytometric analysis of circulating megakaryoblasts in chronic myeloid leukaemia

The immunophenotype (a), ultrastructural features (b) and cell kinetics (c) of circulating megakaryoblasts have been studied in two cases of pure megakaryoblastic and one case of mixed (myeloblastic, megakaryoblastic) cell proliferation in chronic myeloid leukaemia (CML). (a) The blast cells showed early megakaryocyte differentiation antigen (HLA-DR), platelet specific GpIIIa (CD61) and GpIIb-IIIa (CD41) antigens in different percentages. (b) The megakaryoblasts were recognized by the presence of platelet GpIIIa (CD61) demonstrated by an immunoelectron microscopic method. The labelled cells were "lymphocyte-like" megakaryoblasts and cells with features of cytoplasmic maturation (demarcation membranes, alpha granules and vacuoles). (c) Cellular DNA content of the megakaryoblasts was measured by propidium iodide (PI) staining of cells expressing platelet GpIIIa (CD61). Flow cytometric (FC) DNA analysis revealed no aneuploidy and high ploidy (greater than 4N) cell population. In the two cases of pure megakaryoblastic proliferation a high percentage of the megakaryoblasts were in the S-phase, while the non-megakaryoblastic cell fraction showed no elevated S-phase compartment. It is concluded that in CML the circulating megakaryoblasts (1) have a nuclear maturation arrest and accumulation at the level of tetraploid DNA content, (2) surface antigen expression and cytoplasmic organelles show a tendency to mature and (3) in pure megakaryoblastic proliferation the myeloid cells are not in the cell compartment showing high proliferation.

[T gamma-lymphoproliferative disease]

The case of a rare type of T-cell malignant lymphomas, clinically with a relatively favorable course, a T gamma-lymphoproliferative disease (T gamma-cell chronic lymphocytic leukaemia) was presented. The cytomorphological, cytochemical, immuncytochemical and cytogenetical markers and functional tests of the peripheral blood lymphocytes from the patient were tested. The leukaemic cells with light- and electron microscopy showed the so called LGL (large granular lymphocyte) morphology with multifocal reactions of acid hydrolase enzymes. These cells also expressed IgG-Fc-receptor, CD 8 monoclonal antibody positivity and a monoclonally rearranged T-cell receptor gen expression. Functionally the patient's lymphocytes developed a blastic response to the T-cell mitogen Concanavalin A (ConA), they suppressed the immunoglobulin production of B-lymphocytes in co-cultures and had a normal NK-activity but decreased ADCC values. The patient was diagnosed by blood, bone marrow and lymph node examination and does not need any therapy. This case was published because of it's diagnostic, immunological and prognostical interests.

Circulating megakaryoblasts in chronic myeloproliferative diseases. An immunoelectron-microscopic study

Ten cases of chronic myeloproliferative diseases with myelofibrosis and circulating megakaryoblasts have been studied. The megakaryoblasts were recognized by the presence of megakaryocyte-platelet-related cell surface antigens, detected by an immuno-electron-microscopic method. They showed a tendency to develop from 'lymphocyte-like' mononuclear cells to relatively mature megakaryocytes. In these latter cells, the cytoplasm was abundant and contained specific organelles and cytoplasmic blebs. Several characteristic features were observed during the maturation of the megakaryoblasts: (1) cells of the megakaryocytic lineage represented by microforms, (2) dysplastic platelets (giant, nucleated and agranular platelets), (3) the shedding of dysplastic platelets brought about by cytoplasmatic membrane inclusions and (4) naked nuclei.