Study of 50 cases of acute leukaemia in childhood

Characteristics of Cell Proliferation in Children's Lymphoblastic Leukemia

The proliferative activity of the bone marrow and peripheral cells of acute infant lymphoblastic leukemia was evaluated by « in vitro » incorporation of thymidine-H3. The proliferative activity of leukemic lymphoblasts proved roughly similar to that already observed in hemocito-myeloblastic acute leukemias of adults. Within the lymphoblastic population, incorporation of tritiated thymidine was distributed very heterogeneously and there was no labelling of the smaller blasts. In the larger blasts, the labelling index increased progressively with the increase in cell diameter. The acute leukemia population can thus be divided into two classes: proliferating and non-proliferating. A study of the proliferative activity of lymphoblasts, contemporaneously in bone marrow and peripheral cells, suggested a division of cases into two groups. In one proliferative activity in the marrow was greater than in the peripheral blood; in the other it was equal to or less than in the peripheral blood. The second group was made up of cases whose clinical features presented a much more marked hepato-splenomegaly and high peripheral leucocytosis. A more detailed study of proliferative activity considering various classes of blasts within the same population showed that, in the first group of patients, the highest percentage of large blast cells is found at bone marrow level, while in the second the percentage of large blasts in the marrow is equal to or less than that observed in the peripheral blood. It was also shown that total proliferative activity is correlated to the percentage of large blasts. On the basis of these findings, one may admit that in first group forms the leukemia cells are generated prevalently in the bone marrow, while in second group forms most leukemic cells are formed elsewhere.

CELLULAR TYPES IN ACUTE LEUKAEMIA: DIAGNOSIS AND SIGNIFICANCE

Two independent observers, one using haematological and the other histological methods, analysed material from 68 patients with acute leukaemia. A correct diagnosis of the cell type of leukaemia was made in 70% of cases by haematological methods, and in 83% of those cases histological examination gave the same result. In two-thirds of the haematologically equivocal cases histological examination provided a positive diagnosis. The finally undiagnosed cases amounted to 12% of the total. The types so diagnosed could not be correlated with any clinical features. Differentiation of the cell types in acute leukaemia showed that children with granulocytic types of acute leukaemia survived for shorter periods than those with other types but in adults the type of cell had no significance when related to survival. In adults the immediate prognosis for all cell types was relatively bad. The unfavourable prognosis attached to a high initial leucocyte count was confirmed.

A case of pure monocytic leukaemia in a child - characterization of cellular morphology, membrane markers, surface glycoproteins and karyotype

A case of pure monocytic, 'Schilling-Type' leukaemia in a 9-year-old boy is described. The leukaemic cells resembled monocytes and were abundantly present in blood and bone marrow. They were strongly alpha-naphthyl-acetate-esterase positive, contained fine PAS-positive granules and did not stain by Sudan B. They were negative for surface bound and intracytoplasmic IgG, but had a high density of membrane Fc-receptors and showed phagocytosis. The surface glycoprotein pattern resembled that of monocytes, but was clearly different from those of lymphocytic and myelocytic cells or those of acute lymphocytic leukaemia cells. The karyotype of bone marrow cells was 44,X, -15, -21, +mar,del(2)(p11), with the missing Y-chromosome located in the marker chromosome. Especially the surface glycoprotein and membrane receptor analyses aided in the accurate classification of the monocytic origin of the leukaemic cells.

Acute nonlymphocytic leukemia in 171 children

The initial features, response to therapy, complications, cause of death, and prognostic factors of 171 consecutive children with ANLL are described and compated to historical data for adults with ANLL and for children with ALL. Major differences between children and adults with ANLL include a higher frequency of CNS leukemia and a lower frequency of early deaths in the children. The most important differences between children with ANLL and ALL are the absence of a peak age of incidence in ANLL and the far better response to therapy in ALL. Among features present at 100,000/mm3 or above, and no palpable hepatomegaly had significantly longer survivals, while patients with platelet counts below 10,000/mm3 had significantly shorter survivals. The frequency and duration of remission were significantly better with three protocols used since 1968 than previously. However, even with these protocols, the results were far from satisfactory, with a complete remission frequency of 66%, a median duration of hematological remission of 6 months, and a median duration of survival of 10 months. The striking contrast of these results in childhood ANLL with current results in childhood ALL underscores the need for novel, imaginative therapeutic approaches for ANLL.

ACUTE MONOCYTIC LEUKAEMIA WITH RESPONSE TO METHOTREXATE

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