Bent Pedersen

The effect of iron chelation on haemopoiesis in MDS patients with transfusional iron overload

Long‐term follow‐up data are presented on changes in peripheral blood counts and Hb requirements of 11 patients with myelodysplastic syndromes (MDS) during iron chelation treatment with desferrioxamine for up to 60 months. The erythroid marrow activity was indirectly evaluated by repeated determinations of the serum transferrin receptor concentration. The efficacy of iron chelation was evaluated by repeated quantitative determination of the liver iron concentration by magnetic resonance imaging.

FUNCTIONAL AND BIOCHEMICAL PHENOTYPE IN RELATION TO CELLULAR AGE OF DIFFERENTIATED NEUTROPHILS IN CHRONIC MYELOID LEUKAEMIA

Circulating polymorphonuclear neutrophils from most patients with chronic myeloid leukaemia (CML) show a number of biochemical and functional defects. In addition to low alkaline phosphatase activities, prolonged intravascular circulation times (Athens et al, 1965; Galbraith, 1970; Meuret et al, 1973), subnormal adhesiveness to glass (Brandt, 1965; Penny et al, 1966) and nylon surfaces (Taub et aI, 1980), delayed emigration to extravascular sites (Perillie &Finch, 1960; Senn P t al, 1971; Banerjee et al, 1972), reduced phagocytic and bacterial killing activities (Brandt, 1967; Rosner et al, 1970; Olofsson et al, 1976) as well as subnormal contents of lactoferrin (Broxmeyer et al, 1977) and lysozyme (Odeberg et al, 1975) have been observed. The cause or causes of this variety of defects remains incompletely understood. The defects may be simple stigmata of the intrinsic leukaemic nature of the cells. Alternatively, the cells may be intrinsically normal and their phenotypic abnormalities due to alterations in the physiological environment which are secondary to the leukaemic condition. The intention of this Annotation is to discuss the various causal possibilities in the light of recent experimental observations. The possibility that a common cause underlies these phenotypic defects presupposes that they are mutually linked in some way or other. There is evidence that this is the case: the various functional and biochemical changes appear to develop together and to become most marked in the segmented forms, as shown by the following studies. CML neutrophils which have emigrated to an extravascular site of mechanical injury (‘skin window’ technique) are more active in phagocytosis (Tornyos, 1967) and show higher alkaline phosphatase activities (Perillie &Finch, 1961) than is observed in the corresponding circulating population. Brandt (1 965) investigated the relation between adhesiveness to glass beads and phagocytic uptake of carbonyl iron particles in two CML patients and found that the more adhesive cells were also the more active phagocytes. Release of lactoferrin from normal neutrophils promotes adherence to endothelial cells (Oseas et al, 1981), which suggests a link between low lactoferrin contents in CML neutrophils and reduced adhesiveness. Furthermore, phagocytic and alkaline phosphatase activities have been shown to be associated characteristics in CML neutrophils (Pedersen & Hayhoe, 19 71). Together, these studies suggest that adhesiveness, phagocytosis, alkaline phosphatase

Specific minor chromosome deletions consistently occurring in myelodysplastic syndromes

Forty-two patients with refractory anemia with or without sideroblasts have been investigated cytogenetically one to nine times (mean, 3) over a period of 1-36 months (mean, 16). The initial investigation showed numerical and/or major structural abnormalities [t(3;3), 5q-, -7, or 7q-, 11q-] in nine patients (21%). In addition, minimal terminal deletions were observed in 2p, 8p, 9p, 11p, 12p, 17p, 17q, 20q, and Xp. The detection of these deletions, which have not been reported earlier, was due to consistent application of the high resolution technique, G-banding without trypsin, and metaphase photography on large size negatives. Each deletion occurred as a clone on one or more occasions in 1-17 patients (mean, 7). One or other clonal minimal deletion was observed in 32 patients (76%). Preliminary indirect evidence indicates that alone or together with other factors the deletions promote leukemic transformation of refractory anemia.

Myelodysplastic syndrome in a child with constitutional trisomy 8 mosaicism and normal phenotype

Trisomy 8 is a frequently acquired cytogenetic abnormality in myeloid malignancies, but may also represent a constitutional chromosome abnormality with a wide phenotypic variation. We report a case of myelodysplastic syndrome (MDS) that developed in a child with trisomy 8 mosaicism and normal phenotype. Bone marrow (BM) cells all showed trisomy 8 with additional clonal abnormalities in most cells. Based on the present case and a review of previously published cases of myeloid malignancies in patients with trisomy 8 mosaicism, it appears likely that the malignant cells developed from the trisomic cell population, suggesting that constitutional trisomy 8 may be a predisposing condition to myeloid malignancies. Trisomy 8 in malignant cells is usually considered an acquired abnormality, but this implies a risk of ignoring a constitutional trisomy 8 mosaicism. Examination for constitutional trisomy 8, despite a normal phenotype, may therefore be warranted in hematologic malignancies with trisomy 8 of BM cells to evaluate further the possible association and to preclude erroneous use of trisomy 8 as a tumor marker.

Relation of blast cell survival and proliferation to chemotherapy resistance in AML.

We have investigated the in vitro blast cell survival (viability) and drug resistance to cytosine arabinoside (Ara‐C), daunorubicin (Dau), mitoxantrone (Mitox) and aclarubicin (Acla) of fresh leukaemic blast cells from 80 patients with newly diagnosed acute myeloid leukaemia (AML) employing the semiautomated colourimetric MTT(3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide)‐assay. In 15 cases we concurrently investigated the relation between in vitro blast cell survival (MTT assay) and blast cell proliferation (3H‐thymidine incorporation) in the presence and absence of myeloid growth factors (GFs) G‐CSF, GM‐CSF and IL‐3 (individually and in combination). A highly significant correlation was found between blast cell survival and blast cell proliferation (r = 0.87, P < 1 × 10−4). Furthermore, in 40 evaluable adult patients who completed intravenous induction chemotherapy and were evaluable for response to chemotherapy we found a positive correlation between in vitro blast survival (MTT assay) and response to chemotherapy with high blast survival being associated with poor response to chemotherapy (P = 0.05). Moreover, in a multivariate analysis, high blast cell survival was significantly associated with high CD13 expression and monocytic phenotype (P = 0.0003 and P = 0.02, respectively). Furthermore, we found an inverse relationship between the baseline proliferation of the blasts and the magnitude of response to the GFs (P < 0.02), indicating that cells with low baseline proliferation were more readily stimulated by growth factors. Finally, we found a significant correlation between leukaemic cell survival and cellular drug resistance towards Dau (P = 0.001) and Mitox (P = 0.03), but not towards Ara‐C (P = 0.68) and Acla (P = 0.13). We conclude that high in vitro leukaemic cell survival is associated with drug resistance in vivo and in vitro, and furthermore is correlated with high blast cell proliferation and some adverse prognostic factors previously identified in AML.

Survival of patients with t(1;7)(p11;p11): Report of two cases and review of the literature☆

t(1;7)(p11;p11) is a relatively rare chromosome aberration, in most cases associated with acute myeloid leukemia or myelodysplasia. Earlier, many patients received chemotherapy for a malignant disease. The prognosis is usually poor. I describe two patients and review the literature. Thirty-six of the 73 had a history of previous exposure to chemotherapy or radiotherapy. Alkylating agents had been used in 29. The median survival after observation of the translocation was only 11 months, a much shorter survival time than is common for patients with secondary hematologic disorders. Sex, diagnosis, hemoglobin concentration, and percentage of metaphases containing t(1;7) were independent prognostic factors. Despite its relation to earlier chemotherapy, the chromosome aberrations associated with t(1;7) lack the cytogenetic features characteristic of therapy-induced disorders.

A factor encoded by 7q31 suppresses expansion of the 7q- clone and delays cytogenetic progression

Deletion of part of chromosome 7q (7q-) is a consistent aberration in human acute leukemias and myelodysplasias, especially in patients with a history of genotoxic exposure. The deletion is usually associated with a short survival. Loss of a number of different 7q segments has been described, but still it is not known whether different deletions imply differences in survival. We have investigated the possible importance of loss of different segments in 77 7q- patients studied with high-resolution banding. Thirty-six were examined in our laboratory and 41 were published cases. We found that when the 7q- marker contained the 7q31 band, the 7q- clone was smaller than when the band had been lost (p = 0.011), and the patients survived longer (p = 0.004). Further, karyotypes with complex aberrations were less frequent (p = 0.012). These results indicate that genetic information in 7q31 delays cytogenetic and clinical progression of myeloid disease with 7q-. Our results do not tell, however, whether this is due to direct tumor suppressor activity of a 7q31 gene or due to a more indirect effect.

13-cis retinoic acid treatment of myelodysplastic syndromes.

Of eight patients with primary myelodysplastic syndrome (MDS) treated with Roacutane (13-cis retinoic acid, Roche, Basel, (13-RA)) 20 mg/m2 for 6 weeks and an additional 100 mg/m2 for 4 weeks (3 patients), 4 responded either with a slight increase in peripheral blood neutrophil count or a decrease in myeloperoxidase deficient neutrophils. In agar cultures 2 patients showed a concurrent increase in growth of day 11 colonies and clusters. In 2 of the patients a decrease in the number of immature bone marrow cells positive for the myeloid antibody anti-My7 was observed. Only minor alterations were seen in natural killer cell activity. In 4 patients showing clonal chromosomal abnormalities before treatment a disappearance of minor clonal abnormalities during treatment was observed, and in 3 chromosomal abnormalities reappeared after cessation of therapy. Even though the overall impact of 13-RA on the hematopoietic system was minor, the increase in myeloperoxidase normal granulocytes in the blood and the decrease in My7 positive cells and in clonal chromosomal abnormalities warrants further interest in this agent as a treatment modality in MDS. The side effects, especially experienced by the patients receiving 100 mg/m2, were, in spite of symptomatic treatment, of such a degree that only low dose treatment (10-20 mg/m2) administered for prolonged periods of time (3-6 months) would seem recommendable.

Many unbalanced translocations show duplication of a translocation participant. Clinical and cytogenetic implications in myeloid hematologic malignancies

If a translocation is followed by loss of one of the two derivative chromosomes, the result is an unbalanced translocation, showing monosomy for the segments making up the lost derivative. We have found that in most unbalanced translocations, a third event takes place: a morphologically normal copy of one of the two translocation participants is added to the karyotype. This creates a complex abnormal karyotype with monosomy, disomy, and trisomy for different segments of the translocation participants. We have examined 82 unbalanced translocations from 77 patients, 73 of whom had a myeloid hemopoietic malignancy. Acquisition of a normal copy of a translocation participant was found in 49 translocations. Twenty‐five of these showed trisomy for 1q. In 16 of the 25 1q‐trisomic cases the translocation was t(1;7)(q10;p10) (trisomy for 1q and monosomy for 7q). Patients with trisomy for 1q were younger than the remaining patients. Whereas those with t(1;7))(q10;p10) showed brief survivals, those with trisomy 1q but monosomy for regions other than 7q survived longer than the remaining patients. We conclude that most unbalanced translocations involve a partial trisomy, that 1q is trisomic far more frequently than any other segment, and that partial trisomy is associated with patient age and survival. Am. J. Hematol. 64:161–169, 2000.

Translocation (1;16) identified by chromosome painting, and PRimed IN Situ-labeling (PRINS): Report of Two cases and Review of the Cytogenetic Literature

We used the molecular cytogenetic in situ techniques chromosome painting and PRimed IN Situ labeling (PRINS) to elaborate the cytogenetic observations in two cases of the rare aberration der(16)t(1;16), which occurs in a wide variation of hematologic and nonhematologic malignancies [1-3]. Review of the literature showed that, in contrast to the chromosome 1 breakpoint, the breakpoint on chromosome 16 is associated with diagnosis as well as patient age.