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In the five years period 1969-1973, 22 cases of acute lymphoblastic (ALL) and 75 of acute myeloid leukaemia (AML) were observed in adults. In ALL, complete remission was obtained in 61% of cases. The median duration of remission worked out to be 3 months in the group of patients who died and more than 6 months in the patients still alive. The mean survival time was 7,8 and more than 10,6 months respectively. The various regimens of treatment used in the phase of induction appeared to be equally effective, whilst cyclic chemotherapy was found to be preferable in maintaining remission. As far as AML is concerned, complete remission was achieved in 25% of the patients with stem cells leukaemia, 50% in myeloblastic leukaemia and 33% in mielyomoocytic leulaemia. The median duration of remission was 3,5 and 9 months respectively. No case of promyelocytic leukaemia and erythroleukaemia achieved complete remission. The mean survival time was 3,4 months in stem cells leukaemia, 6 months in myeloblastic leukaemia, 6,6 months in myelomonocytic leukaemia, 0,4 months in promyelocytic leukaemia and 2,5 months in erythroleukaemia. In stem cells leukaemia, the highest frequency of remission was found in patients aged 13 to 20 years, whilst in myeloblastic and myelomonocytic leukaemia the most favourable results were obtained in patients aged 50 to 70 and 20 to 50 respectively. The longest mediam duration of remission and the best survival time was obtained in myelomonocytic leukaemia. The best rate of remission was achieved in the patients whose initial leukocyte count ranged from 10.000 to 50.000/mm-3. No patient with an initial WBC count above 50.000/mm-3 entered complete remission. The frequency of complete remission worked out to be much higher in the patients treated with cyclic chemotherapy according to the Hammersmith protocol, except in the case of stem cells leukaemia.

The presence of immune-complexes (IC) and antipolymorphonuclear neutrophil (PMN) autoantibodies was investigated in 28 patients with chronic idiopathic neutropenia and normal or hypercellular bone marrow, 19 with a metamyelocyte arrest and 9 with more dysplastic features. The in vivo interaction between IC and PMN membrane receptors was evaluated by means of the PMN immunohistological technique. Circulating IC was evaluated with the C1q and rheumatoid factor agglutination inhibition techniques. An anti-PM autoantibody activity was investigated by challenging Fab obtained from the sera of 22 patients with PMN from normal donors. IC were detected in a high percentage of patients; in no case could an anti-PM autoantibody activity be seen. Most patients with a metamyelocyte arrest, but only 1 with more dysplastic features, were IC+. During a follow-up period of l2-52 months, none of the patients with a metamyelocyte arrest (IC+) developed anaemia, thrombocytopenia or leukaemia, while anaemia and thrombocytopenia were almost the rule in the clinical course of dysplastic bone marrow IC- patients: 2 of them developed acute myeloblastic leukaemia.

223 cases with chronic lymphoid leukemia (CLL) were subjected to a prospective study on the presence of adeno- and splenomegaly at diagnosis and their subsequent variation. Subjects with no initial organ involvement were usually female (76%) and of old age (mean 69.2 years). Adenopathy or combined lymph node and spleen enlargement were inversely proportional to the mean age at diagnosis. Subsequent organ enlargement was noted in 11.7% of patients with no initial organomegaly, splenomegaly in 15% of patients with adenopathy only and adenopathy in 15% of patients with splenomegaly only. Except in the few cases with leukopenia, particularly high leuklocyte levels were noted in patients with splenomegaly (with or without adenopathy). Anemia at diagnosis was not related to the degree of organ enlargement. It is suggested that qualitative and also quantitative differences in organomegaly in CLL merit further study to establish their underlying mechanisms. CLL must be seen as something more complex than the simple mechanical expression of progressive lymphocyte accumulation.

Chronic myelogenous leukemia (CML) granulo-monocyte committed progenitors (CFU-GM) are markedly less sensitive than normal progenitors to the inhibitory action of prostaglandin E (PGE). This phenomenon has been ascribed to their abnormal expression of HLA class II (mainly DR) determinants. Since interferon gamma (IFN-gamma) is a potent inducer of the expression of HLA class II (DR and to a lesser extent DQ) antigens, we have sought to determine the extent to which this agent can modulate both the antigenic pattern of normal and leukemic progenitors and their sensitivity to PGE 1. 72-h preincubation of normal and CML bone marrow cells with or without IFN-gamma does not significantly change DR and DQ expression by CFU-GM. Pre-incubation for 72 h with and without IFN-gamma produces the following changes in PGE 1 sensitivity: (1) normal CFU-GM lose some sensitivity to PGE 1. This is only marginally counteracted by the presence of IFN-gamma. (2) CML CFU-GM, preincubated with IFN-gamma regain a significant sensitivity to high concentrations of PGE 1. Our data confirm the expression of DR molecules on normal and leukemic progenitors. They also show that, although incubation with IFN-gamma for 72 h in a liquid culture system does not significantly affect the expression of HLA class II molecules by progenitor cells, it may increase their sensitivity to PGE, particularly in the case of CML CFU-GM. Thus expression of HLA class II antigens and sensitivity to PGE may be dissociated.

It has been suggested that the expression of some HLA class II antigens, derived from three loci (DR, DP, DQ) is important in the regulation of both the immune response and the response of haemopoietic progenitors to regulation factors, such as acidic isoferritins (AIF), as well as in the interaction between T lymphocytes and erythroid progenitors (BFU-E). Changes in the expression of class II antigens have been reported on the surface of granulo-monocyte progenitors in chronic myeloid leukemia (CML) and correlated to the abnormal proliferation of such cells. In this study, monoclonal antibodies against DR and DQ monomorphic determinants were used to investigate the expression of these antigens on the surface of normal and CML bone marrow and peripheral blood BFU-E by means of complement mediated cytotoxicity. It was found that most normal and leukemic BFU-E express DR antigens. Antigens density tends to be greater on marrow as opposed to peripheral precursors. In addition, leukemic BFU-E are more sensitive to cytolytic treatment than their normal counterparts. Normal BFU-E do not express detectable amounts of DQ antigens, whereas these are present on a proportion of leukemic BFU-E.

Blood or bone marrow samples from 15 patients with newly diagnosed acute myeloblastic leukemia undergoing remission induction treatment with daunorubicin, cytosine-arabinoside and 6-thioguanine were tested in vitro. Leukemic cells were incubated for 24 h at 37 degrees C with or without the drugs alone or in combination. A 3-h pulse with labelled precursors of DNA synthesis (3H-thymidine) or protein synthesis (3H-leucine) was then given separately. In vitro growth, expressed as the percentage ratio between labeled precursor uptake in treated cells and in control cells, was compared with the clinical results obtained. Three patients were not considered evaluable (death occurred too early), 8 had a complete response (CR), and 4 were disease resistant to chemotherapy. Leukemic cells of resistant-disease patients showed a significantly lower growth inhibition than cells taken from CR patients, with each drug alone or in combination, when measured with thymidine. Inhibition of leucine uptake was not related to the clinical outcome.

Nineteen association of leukaemia and tumour were noted in a series of 502 cases of leukaemia: 12/180 (6.6%, compared with 4.7% of 5136 cases in the liteature) for Chr. L.L. (hypogammaglobulinaemia, reduction in single Ig. serious herpes zoster and the T-lymphocyte nature of leukaemia were not more frequent in these associations); 2/102 (1.9%, compared with 2.6% of 1267 cases in the literure) for Chr. M.L.; 5/220 (2.2%, compared with 2.19% of 1138 cases in the literature) for A.L. The mean age of the overall leukaemia series was virtually the same for A.L. (47 yr in a group composed of subjects aged over 12 yr) and Chr. M.L. (48 yr), with the same incidence of association (2.2 and 1.9%), whereas it was 64 yr and 6.6% incidence in Chr. L.L. The bilogarithmic increase in the incidence of tumours with age may itself explain the higher incidence of Chr. L.L. associations. The duration of leukaemia and the age of incidence must be taken into account in any discussion of the significance of such associations.

It has been suggested that the expression of certain HLA class II antigens stemming from three distinct loci (DR, DP, and DQ) is important not only in the regulation of the immune response but also on the response of hemopoietic precursors to factors inhibiting myelopoiesis. Changes in the expression of DR antigens may be involved in the pathogenesis of altered cell proliferation in chronic myeloid leukemia, since they result in decreased sensitivity of the colony forming units, granulocyte-macrophage to prostaglandin E and acidic isoferritins. In studies using monoclonal antibodies against monomorphic DR or DQ determinants, in a complement-dependent cytotoxic assay, it was found that nearly all normal and chronic myeloid leukemia bone marrow colony forming units, granulocyte-macrophage express DR antigens. The dose response curve was similar for both normal and leukemic precursors. Leukemic peripheral blood precursors were more sensitive than were normal peripheral blood precursors. Normal colony forming units, granulocyte-macrophage did not express DQ antigens, whereas these were expressed in varying quantities by leukemic cells. This study shows that, in the patients we studied, leukemic cells express DR antigens in amounts comparable to normal. In addition, varying amounts of DQ antigens may be observed on leukemic but not on normal progenitors, perhaps as a consequence of an increase in the number of antigens also expressed by normal cells, though in an amount below the detection threshold of cytotoxicity techniques.