T-cell functional abnormality in B-chronic lymphocytic leukaemia: evidence of a defect of the T-helper subset

The helper and suppressor capacity of T, T mu (T non gamma) and T gamma cells was assessed in a group of patients with B-cell chronic lymphocytic leukaemia (B-CLL) in a pokeweed mitogen (PWM) stimulated system. The enriched T-cells (E-rosette positive) from all B-CLL cases showed a reduced capacity to induce the differentiation of normal B-lymphocytes compared with normal T-cells (P less than 0.005). After enrichment of the T mu cells, the helper/inducer capacity was still significantly depressed compared with the same fraction from normal controls (P less than 0.01). On the other hand, enriched T gamma cells from B-CLL were effective in suppressing the differentiation of normal B-lymphocytes to a similar degree as normal T gamma cells. These findings are indicative of a deficient T-cell helper function in B-CLL, which appears to be unrelated to the clinical stage of the disease. The fractionation experiments suggest that this functional impairment is not only due to the abnormal T-cell subset distribution seen in the majority of cases, but point to a possible intrinsic defect within the T mu cell population.

[Polycythemic hyperviscosity syndromes]

Packed red cell volume (VPRC) and total blood volume chiefly affect oxygen transport to tissues and produce the syndrome of polycythemic hyperviscosity. Several studies have demonstrated that a raised VPRC increases the blood viscosity and, under a measured pressure, decreases the flow rate in a capillary tube. Reduced flow results in a less effective tissue perfusion. The oxygen transport at different values of VPRC is shown by an inverted arc-like curve: at normal VPRC levels the oxygen transport is optimal. Hypervolemia affects oxygen transport to tissues: at the same VPRC values, hypervolemic patients have a better oxygen transport. In polycythemia vera (PV), hypervolemia may partially reduce the damage due to the increased blood viscosity. However, in some local areas where fixed vessel diameter (from arteriosclerosis) limits the increased blood flow, hyperviscosity may result in a local tissue ischemia. A relative iron deficiency with associated microcytosis due to venesection frequently occurs in PV. It is also associated with a delayed red blood cell filtration which may contribute to hyperviscosity. When thrombocytosis is present, the risk of thrombotic complications is furthermore increased. We report symptoms and signs at the onset in a series of 80 patients affected by PV. All patients have a minimum follow-up of 4 years. We also report the course of the illness, the treatment effectiveness (venesection, dibromomannitol) on clinical symptoms, the survival curve with analysis of prognostic factors at the onset and the causes of death.

Low dose arabinosyl cytosine for treatment of myelodysplastic syndromes and subacute myeloid leukemia

Several agents, including arabinosyl cytosine (ARA-C) at a low concentration, can induce leukemic myeloblasts to mature to a variable extent. The therapeutic implications of this observation are worth investigating. A few case-reports have shown that low dose ARA-C can be useful for treatment of the myelodysplastic syndromes (MDS) and of acute myeloid leukemia (AML). However, no information is available yet on the proportion of patients who can be expected to respond. We treated by low dose ARA-C (20-30 mg/sqm/day i.v. or i.m. for 7-10 days) 20 consecutive patients. A complete remission of 5 months was obtained in one of nine cases of subacute myeloid leukemia (SAML). A partial remission (complete normalization of blood counts with a slight excess of marrow blast cells) was obtained twice in one of 11 cases of MDS. An increase of Hb level (more than 11.5 g/dl) was obtained and maintained for 12 months in a case of MDS. A short-lasting increase of granulocyte count was obtained in another two cases of MDS and SAML respectively. It is suggested that low dose ARA-C can advantageously modify the proliferation to maturation imbalance of leukemic cells by slowing down cell proliferation rate. However, the proportion of patients who respond is probably low. This treatment is at a very early experimental stage and should be probably limited to selected cases of MDS and subacute or acute myeloid leukemia.

Characterization of T-lymphocyte subsets in hairy-cell leukaemia (HCL) by monoclonal antibodies: comparison with Fc gamma, Fc mu receptors and correlation with disease activity

T lymphocytes from 22 patients with hairy-cell leukaemia (HCL) were assessed on the basis of their ability to bind the Fc receptors for IgM (T mu) or IgG (T gamma), and by the capacity to react with OKT monoclonal antibodies. T-cell subsets defined by the presence of Fc receptors for IgM or IgG showed an overall increase in the proportion of T gamma cells and a non-significant decrease of T mu cells, regardless of the clinical state of the disease. Results with monoclonal antibodies showed that in patients with HCL in clinical remission T-cell subsets were normally balanced, while in patients with active disease the distribution and absolute number of T-cell subpopulations appeared markedly impaired, with a significant increase of OKT8 positive cells (suppressor/cytotoxic) and a significant reduction of OKT4 positive cells (helper/inducer) compared both with active disease patients and with normal controls. The OKT4+/OKT8+ ratio was also significantly reduced in patients with active disease compared with those in clinical remission and with controls (0.96 v 1.63 and v 1.94, respectively). Our findings confirm the heterogeneity of T-cell subset positivity defined by monoclonal antibodies and by Fc mu and Fc gamma receptors and suggest that in patients with HCL the distribution of OKT4 and OKT8 positive cells is closely correlated to the clinical state of the disease.

T lymphocyte subsets and colony growth in hairy-cell leukemia

The distribution of T cell subsets and the T colony-forming capacity were assessed in 22 patients with hairy-cell leukemia. An overall increase in the proportion of T gamma cells (31 +/- 15%) and a decrease in Tmu cells (38 +/- 11%) were observed if compared with normal controls (16 +/- 6% for T gamma and 51 +/- 13% for Tmu). In half of the patients, however, these values were normal. T gamma cells were highest in the splenectomized patients and in the 15 non-splenectomized patients T gamma cells were higher in those with active disease. Patients with stable disease or in remission had values close to normal. The T colony-forming capacity of unseparated and enriched T lymphocytes was normal regardless of the T cell subset distribution and clinical stage of the disease. These findings suggest that in HCL, unlike B cell chronic lymphocytic leukemia, the imbalance in Tmu/T gamma ratio does not result in an impairment of the in vitro T colony-forming capacity.

Adolescent and adult acute lymphoblastic leukemia: prognostic features and outcome of therapy. A study of 293 patients

The case histories of 293 adolescent and adult patients with acute lymphoblastic leukemia (ALL) first seen and treated between 1969 and 1979 are reviewed. A complete remission (CR) was achieved in 79% of cases. Male sex, advanced age (greater than or equal to 30 yr old), and early CNS involvement were the major determinants of remission failure. Median duration of first CR was 16 mo, with 23 patients (actuarial proportion 25%) alive and relapse-free at 5 yr. The major determinant of first CR length was white blood cell (WBC) count (best cut-off value at 35 X 10(9)/liter). First CR length was also negatively affected by early CNS involvement, morphological FAB L3 subtype, and B-cell (Smlg+) leukemia, but these features were significantly associated with a high WBC count. First CR length in patients 11-15 yr old did not differ significantly from that of patients 16-59 yr old. The negative prognostic value of T-cell (E+) leukemia was not confirmed in this adult series. CNS prophylaxis provided an effective protection against CNS relapse. Maintenance chemotherapy was apparently more effective when 4 or more than 4 drugs were employed. "Low risk" patients (WBC count less than 35 X 10(9)/liter still relapsed rather frequently (32% at 1 yr, 49% at 2 yr), with 33% of them alive and relapse-free at 5 yr. "High risk" patients (WBC count greater than or equal to 35 X 10(9)/liter +/- early CNS involvement +/- morphological L3 subtype +/- B-cell leukemia) relapsed very quickly (50% at 6 mo. 70% at 1 yr), with only 6% of them relapse-free at 5 yr.

Vindesine effect in myeloid leukemia

Vindesine (VDS), a semisynthetic vinca alkaloid derivative, was given weekly at a dose of 3 mg/m2 as single-agent chemotherapy to seven patients with chronic myeloid leukemia (CML), 17 patients with chronic myeloid leukemia in blastic metamorphosis (CML/BM), and 12 patients with acute nonlymphocytic leukemia (ANLL). A substantial and rapid decrease of leukemic cells was obtained in 31 of 36 patients, and this was independent of cell phenotype and morphology. VDS may improve the results of polychemotherapy of ANLL, and is useful for palliative treatment of CML/BM.

Staging of chronic lymphocytic leukemia

One-hundred and eighty-eight patients with chronic lymphocytic leukemia were analyzed for prognosis based on Rai's staging system. It was found that stages I and II were not homogeneous as to prognosis. Stage II patients presenting with isolated splenomegaly had a long survival and were pooled with stage 0 patients (low risk group, 30% of cases, relative death rate 0.24, median survival greater than 10 yr). Stages I and II patients with a lymphocyte count higher than 40 x 10(9)/liter had a short survival and were pooled with stages III and IV patients (high risk group, 39% of cases, relative death rate 1.91, median survival 3.3 yr). Stages I and II patients with a lymphocyte count lower than 40 x 10(9)/liter made up an intermediate or standard risk group (31% of cases, relative death rate 1.00, median survival 6.2 yr). This modified staging system applied successfully to both old and young patients (more and less than 60 yr old, respectively).

Glucocorticoid receptor and in vitro sensitivity to steroid hormones in human lymphoproliferative diseases and myeloid leukemia

The glucocorticoid receptor (GR) quantitation by a whole-cell assay and/or cytosol technique and the in vitro sensitivity to steroids have been assessed in peripheral blood cells from normal donors and patients with chronic lymphatic leukemia (CLL), acute lymphoblastic leukemia (ALL), lymphosarcoma cell leukemia (LSCL), acute nonlymphatic leukemia (ANLL), and chronic myeloid leukemia (CML). Within the lymphoproliferative diseases, ALL cells exhibited the highest GR concentration (regardless of the method used) and the highest in vitro inhibition of spontaneous [3H]thymidine ([3H]TdR) uptake by glucocorticoids. A significant relationship between GR concentration (whole-cell assay) and in vitro sensitivity to dexamethasone was also found. On the contrary, CLL cells presented the highest sensitivity to glucocorticoids in PHA-stimulated cell cultures. Cells from the only two ALL patients who did not undergo a remission after glucocorticoid-inclusive chemotherapy had both the lowest in vitro sensitivity to dexamethasone and the lowest GR concentration with whole-cell assay. Concerning myeloid leukemia, ANLL patients had GR concentrations slightly higher than those found in the ALL group but exhibited the lowest degree of inhibition of spontaneous [3H]TdR uptake by dexamethasone (stimulatory effects occurred in some cases). CML cells exhibited an inhibition degree by in vitro glucocorticoids significantly higher than that of ANLL cells but not different from that of lymphoproliferative diseases. No clear relationship among GR pattern, in vitro cell sensitivity to glucocorticoids, and clinicohematologic parameters was observed in myeloid leukemia-bearing patients.

T-lymphocyte subsets in healthy splenectomised patients

In 16 normal subjects who underwent splenectomy for traumatic reasons, the T-lymphocyte number (E rosette positive cells) and the proportion of T-cell subsets were assessed on peripheral blood T-lymphocytes. The findings, compared with not splenectomised normal controls, showed other than an increase in the absolute number of T-lymphocytes, mainly a significant increase of T gamma cells (21% +/- 5 vs 13% +/- 4) and a less marked decrease of T mu cells (38.7% +/- 7 vs 51.8% +/- 12). Probably this increase in T gamma cells is irrelevant on the immune response and represents only the effect of the redistribution of T-cell subsets after splenectomy. Alternatively, splenectomy, removing most of the lymphocytes that respond to antigenic stimulation, and, producing an increase in T gamma cells, may contribute to the development of an impaired B-cell response and sometimes to the development of severe infections which occur mainly in splenectomised children.

Chronic idiopathic thrombocytopenic purpura (ITP): site of platelet sequestration and results of splenectomy. A study of 197 patients

51Cr-platelet kinetics study was performed in 197 patients with chronic ITP after corticosteroid therapy had failed to induce a long lasting remission. The incidence of splenic, spleno-hepatic, hepatic and diffuse platelet sequestration site was 58%, 17%, 6% and 19%, respectively. Splenic and spleno-hepatic sequestration sites were more frequent in patients less than 30 years old and in patients with a platelet count lower than 50 x 10(9)/1. 111 patients were splenectomized shortly after the study. Normalization of the platelet count was obtained more frequently in patients with splenic and spleno-hepatic sequestration than in the others. Labelled platelet sequestration site was the best predictor of the outcome of splenectomy. Platelet kinetics is a non-invasive investigation that should be performed early after the diagnosis of chronic ITP in all patients eligible for splenectomy.

Increase in T gamma lymphocytes in B-cell chronic lymphocytic leukaemia. II. Correlation with clinical stage and findings in B-prolymphocytic leukaemia

The proportion of T gamma and T mu lymphocytes was studied in 40 cases of B-chronic lymphocytic leukaemia (B-CLL) and six of B-prolymphocytic leukaemia (B-PLL). The significant increase in T gamma cells, previously reported in two small B-CLL series, was confirmed and shown to be directly correlated with the clinical stages of the disease (P less than 0.01 to less than 0.001). The normal T mu:T gamma ratio (2.3:1) was reversed in B-CLL (1:1.4) and B-PLL (1:1.9). The proportion of T mu cells was decreased but was not related to stage. Our findings suggest that the increase in T gamma cells may be responsible for the hypogammaglobulinaemia of B-CLL. This is supported by two sets of observations. First, serum Ig levels were more often normal in cases in Stages 0 and I than in Stages II-IV (P less than 0.05), while the levels of two or three Ig classes were below normal in Stages II-IV twice as frequently. Secondly, splenic irradiation in one case was followed by a fall in the absolute number of T gamma lymphocytes, a reversion to normal of the T mu: T gamma ratio and an improvement in serum Ig levels. Thus, the imbalance in ;the regulatory T-cell subsets may provide an important clue to understand the pathogenic mechanism of the immunodeficiency in the chronic B-cell leukaemias.

T gamma cell deficiency in idiopathic thrombocytopenic purpura (ITP)

A significant reduction in the proportion and absolute number of circulating T gamma (suppressor) lymphocytes was observed in 15 adult patients with idiopathic thrombocytopenic purpura (ITP). The proportion of T gamma cells was also reduced in the spleen of four patients so investigated. This abnormality was not seen in 5 patients cured by splenectomy whilst it persisted in 3 who remained thrombocytopenic after splenectomy. The proportion of Tmu (helper) lymphocytes in ITP was normal. These findings, similar to those reported in systemic lupus erythematosus, suggest that an inbalance of the immunoregulatory T-cell subsets may be important in the pathogenesis of ITP.

Staging of chronic myeloid leukaemia

The prognostic value of nine clinical and haematological features, recorded at diagnosis in chronic myeloid leukaemia (CML), was analysed in two distinct series of patients. One series (116 cases) was collected at a single hospital over a 12-year period. The second series (139 cases) was collected from a multicentre trial over a 20-month period. Six features were associated with a poor prognosis: splenomegaly (more than 15 cm below the costal margin), hepatomegaly (more than 6 cm below the costal margin), thrombocytopenia (< 150 X 10(9)/l) or thrombocytosis (> 500 X 10(9)/l), a leucocyte count above 100 X 10(9)/l, peripheral blood non-granulated precursors (blast cells) above 1%, and peripheral blood granulated precursors (promyelocytes and myelocytes) above 20%. Depending on the number of negative prognostic factors, patients were divided into three categories: group I (0 or 1 factor), group II (2 or 3 factors) and group III (4,5 or 6 factors). Survival was significantly different in the three groups (P < 0.0005), and this was independent of age (below and above 50). The prognostic value of the classification was confirmed in a third series of 153 patients. We suggest that this classification provides a useful tool to identify prognostic categories in CML, and thus allows a proper allocation of patients to different therapies.

Immunological markers in non-Hodgkin's lymphomas

Membrane markers of lymphomatous cells were studied in 33 patients with non Hodgkin's lymphoma and correlated with morphological diagnosis according to Rappaport's classification. Nodular lymphomas and the majority of lymphocytic lymphomas showed B cell characteristics, whereas only 6 out of 23 with diffuse pattern were B. None of the histiocytic lymphomas were B, 3 were T, and 4 non T-non B. Mixed lymphocytic/histiocytic lymphomas showed different immunological patterns (B, T, non T-non B, B and T). These results confirm the importance of functional classification, which can clarify the pathogenesis of lymphoma.

Growth patterns, cell composition, and mitotic activity of granulocytic aggregates developing in methyl cellulose from human normal marrow cells

Marrow cells from five normal healthy subjects were cultured in methyl cellulose with and without leucocyte conditioned medium. Cultures were examined daily from day 3 to day 14 for the number of granulocytic aggregates and for their cell composition and mitotic activity. Aggregates of different size (small and large clusters, small and large colonies) displayed four distinct and characteristic patterns of growth. Unidentifiable blast cells were very rare throughout culture. The average proportion of recognizable granulocyte precursors (promyelocytes and myelocytes) (PMC + MC) declined during culture from 60% to 34%. There was a negative correlation between the size of the aggregates and their PMC + MC content, but on any day of culture some aggregates consisted mainly or uniquely of PMC + MC, while some others consisted mainly or uniquely of non-proliferating granulocytes. The mitotic index of PMC + MC was much higher than the one previously determined in vivo, and was significantly higher in large colonies than in other aggregates. These results are consistent with the recent demonstration of different CFU-C (sub)populations. It is suggested that differentiation of the aggregates according to their size and kinetics, coupled with cytological examination, can provide a more refined assessment of the assay, which could be useful for further comparison of normal, abnormal, and leukaemic granulocytopoiesis.

Adult acute lymphoblastic leukaemia: study of 32 patients and analysis of prognostic factors

The clinical and haematological characters and the response to therapy of 32 consecutive patients with acute lymphoblastic leukaemia, aged more than 12 years, were reviewed. All patients were given vincristine (V) and (6-methyl) prednisolone (P) for 6 weeks; daunomycin (D) was added in 9 cases, and cyclophosphamide (C) + D in another 10 cases. 3 patients died during induction. 4 patients failed to achieve remission. 25 patients (78%) achieved complete remission (CR). All of them but one received 'prophylactic' central nervous system (CNS) therapy with cranial irradiation and i.t. methotrexate (MTX) and arabinosyl cytosine. CR was maintained with daily 6-mercaptopurine and weekly MTX. Median duration of CR was of 22 months. 2 patients are currently disease-free and off-therapy, 78 and 53 months after diagnosis, respectively. Blast cell membrane markers were studied in 21 consecutive cases: 3 patients had T-cell leukaemia and 2 patients B-cell leukaemia. Prognostic factors were evaluated basing on the present series of 32 patients, and on further 106 cases reported by others. Age (under and above 40) influenced significantly both the CR rate and the length of survival. In patients aged under 40, a circulating blast cell count higher than 25,000/microliter, or a platelet count lower than 50,000/microliter, negatively affected the survival.

Chronic Idiopathic Thrombocytopenic Purpura (ITP) 51-Cr-Platelet Kinetics and Splenectomy in 197 Patients

51cr-Platelet Kinetics was studied in 197 patients with Chronic ITP of which 111 were submitted to splenectomy after the study.

Platelet half life-span was always decreased (< 24 hours).

Platelet, sequestration was splenic, spleno-hepatic, hepato-splenic, hepatic and diffuse in 56%, 18%, 1%, 6% and 19% of patients respectively. Platelet life-span and sequestration were not correlated with sex, age, platelet number, duration and severity of disease.

101 patients with splenic and spleno-hepatic platelet sequestration underwent splenectomy. Their follow-up is 1-5 years. Complete (steady platelet level > 150,000μl) or partial (platelet level in between 80,000 and 15,000/μ1) remission was obtained in 83% and 6% of them respectively. In 10 patients with non-splenic platelet segue-stration complete and partial remission’after splenectomy were observed in 5 and 1 gases respectively.

51Cr-Platelet Kinetics is a reliable and useful predictor of the therapeutic value of splenectomy. However splenectomy should be considered also in selected case with non splenic platelet sequestration.

Acquired Storage Pool Disease in Myeloproliferative Disorders

Defective aggregation and morphological abnormalities of platelets have been observed in myeloproliferative disorders, but their underlying nature is not well understood. We have examined 40 patients, 21 with thrombocythemia. 14 with polycythemia vera and 5 with myelofibrosis. All showed abnormal aggregation with ADP, adrenaline or collagen, and reduced content of platelet serotonin (5HT). ADP levels were also low, and ATP/ADP ratios correspondingly higher than normal. 5HT uptake was abnormal, and in the presence of imipramine, 14C-5HT leaked out of platelets during prolonged incubation in vitro, indicating a defect of the 5HT storage mechanism. Thromboxane B2, measured bv radio immunoassay, was produced in normal amounts when the platelets were challenged with thrombin. 5 U/ml, indicating that the prostaglandin synthesis pathway was unimpaired. The content of α-granule markers, suchas β-thromboglobulin and lysosomal enzyms, was normal in all patients, In essential thrombocythemia. polycythemia vera and in myelofibrosis, the platelet abnormality appears to be associated with an acquired defect of the storage mechanism for nucleotides and serotonin, affecting only some of the platelets. Whether this is due to the production of platelets by an abnormal stem cell line, or to exposure of platelets to inducers of the release reaction in vivo remains to be determined.

Management of nodular sclerosis Hodgkin's disease stage I, II A and B: evidence for a beneficial effect of MOPP on the relapse rate

85 patients with previously untreated Hodgkin's disease with stage I, II A and B nodular sclerosis were treated. 31 of them with stage I and II A were submitted to radiotherapy alone. All are alive, but 9 of them (30%) relapsed. On the contrary, 35 patients with stage I and II A, and 19 with stage I, II and IIE B were submitted to radiotherapy followed by three courses of MOPP. All 54 patients are alive and relapse-free. No severe complication related to chemotherapy was observed. The analysis of results suggests that 3 courses of MOPP can significantly (Ip < 0.00025) reduce the relapse rate in patients with stage I and II nodular sclerosis, eligible for radiotherapy, without increasing morbidity.

Effect of early splenectomy and cyclic acute leukemia-like chemotherapy on the course of chronic myeloid leukemia

This report provides information on the progress of two trials by the Italian Cooperative Study on Chronic Myeloid Leukemia (CML). Both trials were designed in order to test the effect of early splenectomy and of cyclic administration of either arabinosyl cytosine and vincristine plus prednisone, or arabinosyl cytosine plus thioguanine plus daunomycin, on the course of CML and on the survival. A preliminary analysis, performed on September, 1977, suggests that neither splenectomy nor the chemotherapy scheduled have resulted in a significant decrease of the rate of blastic transformation of CML, during the first 2 to 3 years from diagnosis.

The relevance of extramedullary hemopoiesis to the staging of chronic myeloid leukemia

In chronic myeloid leukemia (CML) the spleen and the liver can lodge, trap and release a high proportion of leukemic cells, and are active sites of (leukemic) hemopoiesis throughout the disease. Evidence is provided that spleen and liver volume have a prognostic value, and that marrow, spleen, and liver differ as to cell composition, cell kinetic patterns, functional cell characters, and cell karyotype. In the majority of the patients, extramedullary hemopoiesis seems to be more abnormal than marrow hemopoiesis, supporting the hypothesis that spleen and/or liver can play an important role in the evolution of CML towards the blastic metamorphosis. However, present information on extramedullary hemopoiesis does not allow to identify specific patterns and to establish its relevance to the course of the disease.

Therapy of chronic myeloid leukemia (CML): interim report on protocols CML/73 and CML/74

Current therapies of chronic myeloid leukemia (CML) do not prevent the progression of the disease towards blastic metamorphosis, and have not resulted in a remarkable prolongation of survival. Splenectomy was proposed with the aim of removing a part of the tumor without cytotoxics and of removing a potentially privileged pool of malignant blast cells. Acute leukemia-like chemotherapy was proposed with the aim of eradicating or better controlling the highly malignant subclones that emerge during the chronic phase. A preliminary analysis of 2 clinical trials these therapeutic measures, suggests that splenectomy does not modify the rate of blastic transformation, during the first 2 to 3 years from diagnosis. Also the rate of blastic transformation is similar for patients receiving hydroxyurea at first, and arabinosyl cytosine (ARA-C), vincristine (VCR) and prednisone (P) thereafter, as for patients receiving from the clinical onset of CML a more intensive chemotherapy with ARA-C, thioguanine (TG) and daunomycin (DAUNO), but not VCR + P.

Chromosome radiation-induced aberrations in patients with Hodgkin's disease. Possible correlation with second malignancy?

The karyotype of peripheral blood lymphocytes has been studied in a group of patients with Hodgkin's disease. Before any therapy, the karyotype was either normal or aneuploid. A few months after radiotherapy (total nodal irradiation) a conspicuous amount of structural chromosome aberrations was found. Three to six years after completion of radiotherapy, the lymphocyte karyotype was almost normal, even if stable ionizing radiation-induced aberrations were still detectable. This is consistent with the normal behaviour of these patients and with the long-lasting effect of radiations on nuclear D.N.A. Owing to the close relationship between ionizing raditions and chromosome aberrations on one hand, and abnormal karyotypes and tumors on the other, it cannot be overlooked that these aberrations may play an important role, together with other carcinogenic factors, in the development of second malignancies in these patients.