UMLS:C0026986 - FACTA Search

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Query: UMLS:C0026986 (myelodysplastic syndrome)
14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 64-year-old man had urticaria pigmentosa and myelodysplasia (refractory anemia with excess blast cells; partial trisomy 8 syndrome) without increased numbers of marrow mast cells. Clonal marrow assays in agar demonstrated normal to increased colony-forming units of granulocytes/macrophages. In long-term liquid cultures containing mast cell growth factor (interleukin 3), his marrow cells proliferated after 3 weeks to produce abnormal myeloid precursors similar to those in the corresponding marrow aspirate specimen. Cells with basophilic-staining granules were less abundant in comparison with normal marrow specimens cultured similarly. These results suggest that the mast cells in this patient are not of the same clone as the preleukemic marrow cells, although the possible marrow-cell origin of urticaria pigmentosa mast cells cannot be excluded. Previous reports suggest that urticaria pigmentosa without systemic mastocytosis occurs as a nonspecific abnormality in a variety of myeloid, lymphoid, and nonhematologic malignancies. Our data also support this hypothesis that urticaria pigmentosa is a reactive process rather than a manifestation of clonal proliferation of the primary malignancy.
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PMID:Urticaria pigmentosa and preleukemia: evidence for reactive mast cell proliferation. 205 Aug 59

In vitro growth of primitive hematopoietic progenitors is severely impaired in the myelodysplastic syndromes (MDS). To determine if the c-kit ligand mast cell growth factor (MGF) can improve progenitor growth in MDS, we evaluated in vitro responsiveness of bone marrow progenitors from 25 patients to MGF and/or GM-CSF, interleukin-3 (IL-3) and PIXY 321, and examined the relationship between progenitor response and cellular expression of the c-kit receptor. MGF and erythropoietin gave rise to macroscopic colonies and dose-dependently increased CFU-GEMM and BFU-E up to 27-fold in 15 (60%) and 20 (80%) patients, respectively. Among 17 patients with absent growth in lymphocyte-conditioned media, MGF stimulated CFU-GEMM recovery in 59%, compared to 23% with PIXY 321, 12% with IL-3 and 8% with GM-CSF. Cytokine combinations did not augment recovery of erythropoietin-dependent progenitors above that achieved with MGF alone. MGF and/or IL-3 were comparatively weak stimulants of CFU-GM formation, whereas GM-CSF and PIXY in combination with MGF increased colony number 2- to 15-fold in 60 and 70% of patients, respectively, while preserving maturation competence as evidenced by colony composition and increased colony/cluster ratio. The stimulatory effects of MGF were observed in all morphologic categories of MDS except chronic myelomonocytic leukemia. A mononuclear cell population expressing the c-kit receptor was identified by flow cytometry in 57% of cases. Neither SR-1 reactivity nor cytogenetic pattern predicted progenitor response to MGF. These data indicate that MGF improves the colony-forming capacity of hematopoietic progenitors in MDS and is a potent co-stimulant of multipotent and committed progenitor recovery. The heterogeneity in MGF responsiveness implies an intrinsic defect in growth regulation not explained by cellular loss of c-kit display.
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PMID:Mast cell growth factor (c-kit ligand) restores growth of multipotent progenitors in myelodysplastic syndrome. 751 48

Autonomous, factor-independent growth and differentiation of malignant cells in preleukemic and leukemic disease states is a well-recognized phenomenon and is often associated with a poor prognosis. Mast cells are distinct hematopoietic cells and express a unique profile of antigens. Growth and differentiation of normal mast cells is dependent on mast cell growth factor (MGF), the ligand of the c-kit protooncogene product. In this study, we screened for mast cell-lineage involvement in 52 patients suffering from myeloid leukemias, myelodysplastic syndromes (MDS), systemic mastocytosis, or other diseases by probing for mast cell-related molecules (c-kit, tryptase, histamine, and MGF) and by analyzing kit ligand/MGF-independent growth of mast cells in long-term suspension culture. Of the 52 patients tested, 2 patients with refractory anemia with excess of blast cells in transformation and 1 patient suffering from chronic myeloid leukemia blast crisis (CML-BC) were diagnosed as mastocytic disease. These patients were characterized by complex chromosomal abnormalities, splenomegaly, high percentages of circulating metachromatic cells (5% to 25%), high levels of cellular tryptase (> 10 ng/10(5) peripheral blood mononuclear cells/mL) and a tryptase/histamine (ng:ng) ratio greater than 1. The metachromatic cells expressed the mast-cell-related surface antigen c-kit, but not basophil-related antigens (CD11b, CDw17). Furthermore, in these 3 patients, spontaneous, MGF-independent growth of mast cells along with spontaneous synthesis of tryptase was demonstrable in long-term culture. No autocrine production, paracrine production, or overproduction of MGF was found. The spontaneous growth of mast cells could neither be abbrogated by addition of monoclonal antibodies (MoAbs) to c-kit nor by MoAbs against MGF (< 5% inhibition), whereas factor (MGF)-dependent differentiation of mast cells in these patients could be abbrogated by MoAbs to c-kit or MoAbs to MGF (> 70% inhibition, P < .001). In addition, serum MGF levels in these patients were within the normal range and MGF could not be detected in cell-free culture supernatants. All 3 patients showed rapid progression of disease and had a survival time of less than 1 year. In conclusion, we describe a unique form of transformation in MDS and CML-BC characterized by mast cell lineage involvement and factor-independent differentiation of mast cells. This form of leukemic transformation has to be delineated from chronic myeloid leukemia with basophilia or basophil crisis, from primary mast cell leukemia, and from monocytic leukemias and myelodysplastic disorders associated with basophilia.
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PMID:Kit ligand/mast cell growth factor-independent differentiation of mast cells in myelodysplasia and chronic myeloid leukemic blast crisis. 752 72

Ineffective erythropoiesis due to an impaired response to erythropoietin (EPO) is a prominent abnormality in myelodysplastic syndromes (MDS). The growth factor kit ligand (KL) may restore the in vitro erythroid colony-forming response to EPO in a subset of patients. The inability of MDS erythroid progenitors to react properly to EPO and/or KL has not been resolved. We have investigated erythropoietin receptor (EPO-R) and KL receptor (c-kit) expression in 15 cases of MDS by FACS analysis. The percentage of bone marrow cells expressing the EPO-R from patients with MDS were comparable to normal marrow. No apparent correlation was found between the number of MDS cells coexpressing the EPO-R and CD34 and impaired erythroid response. C-kit was expressed in most MDS patients, including those not responding to KL in EPO-induced cultures. In nine MDS cases the different splice variants of the EPO-R were analyzed. MDS cells, like normal marrow, expressed the full length EPO-R. These results show that impaired erythroid response in MDS cannot be explained by a quantitative lack of receptors for EPO or KL and that most likely suppression of erythroid response is caused by defective receptor signalling following ligand binding, representing a functional defect within the receptor itself or at a level downstream of the receptor.
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PMID:Erythropoiesis in myelodysplastic syndrome: expression of receptors for erythropoietin and kit ligand. 864 63

In the present study, we analyzed the capacity of CD34+/CD36- sorted bone marrow cells of myelodysplasia patients (n = 4) to differentiate along the erythroid lineage in the presence of erythropoietin (Epo) and mast cell growth factor (MGF). Two subgroups could be identified. In 6 patients, a normal number of burst-forming units-erythroid (BFU-Es) were cultured from CD34+/CD36- sorted cells. Cells from these patients did have the capacity to differentiate to colony-forming units-erythroid (CFU-Es) progenitors in cell suspension cultures with Epo plus MGF followed by Epo in the culture assay. Moreover, the cells became CD34-/CD36+/gly-cophorin A (GpA)+ after 7 days of culture with Epo plus MGF, a pattern comparable to that of normal progenitors. In contrast, in 8 patients, a different pattern was observed. No BFU-Es or a low number of BFU-Es were cultured from the CD34+/CD36- sorted cell fraction that was, in most of the cases, incapable of differentiating to CFU-E progenitors. Flow cytometry of the sorted population showed that, after 7 days of culture with Epo plus MGF, a high proportion of CD34+/CD36- cells persisted, whereas a low proportion of cells became CD34-/CD36+/GpA+. The unresponsiveness is not caused by the used growth factor combination, because the addition of interleukin-3 did not correct the defect. Evi-1 expression was studied in 9 cases to show whether an aberrant Evi-1 expression correlates with a disturbed erythroid development. Evi-1 expression was shown in 4 of 9 cases, whereas 3 of 9 cases did have a disturbed erythroid differentiation. In summary, the results show that the defects in the erythroid development in a subpopulation of patients with myelodysplasia is localized at an early stage of the erythroid differentiation and is associated with the persistent expression of the CD34 antigen and, in some cases, with the expression of Evi-1.
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PMID:The supportive effects of erythropoietin and mast cell growth factor on CD34+/CD36- sorted bone marrow cells of myelodysplasia patients. 869 98

Mast cells and blood basophils are distinct hemopoietic cells. They can be distinguished from each other and from all other lymphohemopoietic cells using antibodies against surface receptors or stored cytoplasmic molecules. In patients with myelodysplastic syndromes (MDS) or myeloproliferative syndromes (MPS), an elevation of metachromatically granulated cells (MCS) is frequently seen. These cells can be classified as basophils or mast cells using monoclonal antibodies (mAbs) against leukocyte antigens, including mast cell tryptase, c-kit (= mast cell growth factor [MGF] receptor), interleukin-3 receptor alpha chain (IL-3R alpha = CD123), and CD11b (C3biR). In a stable phase of MDS or MPS, the circulating MCS usually are basophils (histamine+, tryptase-, c-kit-, IL-3R alpha +, CD11b+). In an accelerated or terminal phase of disease, however, mast cell lineage involvement and circulating mast cell precursors (histamine+, tryptase+, c-kit+, IL-3R alpha-, CD11b-) are found in a subset of patients. The use of mAbs against mast cell antigens and granulocyte antigens is diagnostic in these patients.
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PMID:Mast cell-lineage versus basophil lineage involvement in myeloproliferative and myelodysplastic syndromes: diagnostic role of cell-immunophenotyping. 881 68

Growth factors are commonly included in protocols for the treatment of acute myeloblastic leukemia (AML). Because the response of blast stem cells in culture to growth factors might influence the contribution of factor to clinical outcome, we studied 42 patients with AML or severe myelodysplasia. Peripheral blood blast cells were cultured in a clonogenic assay at three cell concentrations and with the following combinations of growth factors: no added growth factor (NF), G-CSF, GM-CSF, Kit ligand (KL), G-CSF + KL, GM-CSF + KL, and G-CSF + GM-CSF + KL. The slope of the line relating cell number plated to colony formation was calculated by least squares. The slopes were used to form three equally sized groups of patients. Marked heterogeneity was found in response of the blast populations to factor. A few general conclusions emerged: (1) autonomous blast populations are very rare; (2) although usually a population responds better to one of the growth factors than to others, seldom is the response exclusively to one factor; (3) when more than one factor is included in the cultures, synergism is usually seen. Significant associations were seen between successful remission induction for low slope values in cultures with NF or KL alone. For remission, but not survival, associations were found with intermediate values of slope in cultures with G-CSF + KL and GM-CSF + KL. We conclude that measurements of growth factor response are feasible and yield clinically useful data.
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PMID:Response of the blast stem cells of acute myeloblastic leukemia to G-CSF, GM-CSF, or the ligand for C-KIT, alone or in combination. 887 30

Myelodysplastic syndromes (MDS) may be accompanied by systemic mastocytosis. The mechanisms which play a role in the evolution of mastocytosis, however, are not well understood. We report on a case of refractory and anemia with ringed sideroblasts (RARS), and co-existing bone marrow mastocytosis. Compact mast cell (MC) infiltrates were detected in bone marrow sections by immunohistochemistry using an antibody to tryptase. In addition, the MC were found to express c-kit, the tyrosine kinase receptor for MGF (mast cell growth factor = stem cell factor, SCF). Activating point mutations in the kinase domain of c-kit (often found in mastocytosis) were not detectable. However, the mononuclear cells (MNC) of the bone marrow expressed mRNA specific for MITF, a transcription factor that regulates expression of c-kit and differentiation of MC. Surprisingly, the c-kit ligand SCF was found to augment expression of MITF mRNA in bone marrow MNC. Whether this augmentation represents a general response (preventing loss of growth factor receptor expression during cell maturation) common to all types of hemopoietic progenitors, or is confined to (some forms of) mastocytosis, remains unknown.
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PMID:Detection of mi transcription factor (MITF) mRNA in a case of myelodysplastic syndrome and bone marrow mastocytosis. 955 2

Myelodysplasia (MDS) is mostly characterized by a normal or increased number of normoblasts in the bone marrow and an impaired in vitro colony formation. In the present study we analyzed whether this might be due to a disconnection between proliferation and differentiation. CD34+/CD36- sorted bone marrow cells of 18 MDS patients were cultured in a clonogenic and suspension culture assay in the presence of erythropoietin (Epo) and mast cell growth factor (MGF). Burst-forming units erythroid (BFU-E, 75 +/- 88/10(4) CD34+ cells, X +/- s.d.) and colony-forming units E (CFU-E) were observed in eight of the 13 cases (62%) with refractory anemia with or without ring sideroblasts (RA and RARS) and one of the five cases with RA with excess of blasts or in transformation (RAEB and RAEB-T). Suspension cultures with CD34+/CD36- sorted cells with Epo plus MGF demonstrated an 8.9 +/- 6.5-fold expansion after 7 days in cases with >10 BFU-E/10(4) CD34+/CD36- cells while cases with <10 BFU-E/10(4) CD34+/CD36- cells demonstrated 1.0 +/- 0.8-fold expansion especially in cases with RAEB/RAEB-T. FACS and morphology analysis after 7 days of suspension culture demonstrated partial differentiation along the erythroid lineage in cases with RA/RARS (75%) and RAEB/RAEB-T (66%) reflected by the presence of erythroblasts and normoblasts with variable expression of CD34, CD36 and Glycophorin A. In cases with erythroid colony formation 69 +/- 24% of the cells were CD34-/CD36+ and in cases with <10 BFU-E/10(4) CD34+ cells 18 +/- 16% of cells were CD34-/CD36+. Iron staining showed the presence of ring sideroblasts in two cases with RARS indicating that the cells originate from the abnormal erythroid clone. Finally, it was shown that cases with an impaired proliferative response demonstrate an enhanced binding of Annexin-V on CD34+ cells during the first days of the cell suspension culture phase. These results suggest that a defect in the proliferative response is most pronouncedly expressed in MDS whereas a subpopulation of cells retain the capacity to differentiate between transition to a terminated stage.
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PMID:CD34+/CD36- cells from myelodysplasia patients have a limited capacity to proliferate but can differentiate in response to Epo and MGF stimulation. 1008 48

We studied telomerase regulation and telomere length in hematopoietic progenitor cells from peripheral blood and bone marrow from patients with acute and chronic leukemia and myeloproliferative diseases. CD34+ cells from a total of 93 patients with either acute myeloid leukemia (AML; n = 25), chronic myeloid leukemia (CML; n = 21), chronic lymphocytic leukemia (CLL; n = 18), polycythemia vera (PV; n = 16), or myelodysplastic syndromes (MDS; n = 13) were analyzed before and in 19 patients after ex vivo expansion in the presence of multiple cytokines (kit ligand, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor plus erythropoietin). Compared with hematopoietic progenitor cells from normal donors (n = 108), telomerase activity (TA) was increased 2- to 5-fold in chronic phase (CP)-CML, CLL, PV, and MDS. In AML, accelerated phase (AP) and blastic phase (BP)-CML, basal TA was 10- to 50-fold higher than normal. TA of CP-CML CD34+ cells was up-regulated within 72 h of ex vivo culture, peaked after 1 week, and decreased below detection after 2 weeks. In contrast, TA in AP/BP-CML and AML CD34+ cells was down-regulated after 1 week of culture and decreased further thereafter. The expansion potential of CD34+ cells from patients with leukemia was considerably decreased compared with CD34+ cells from normal donors. The average expansion of cells from leukemic individuals was 6.5-, 2.3-, 0.6-, and 0.2-fold in weeks 1, 2, 3, and 4, respectively, whereas expansion of normal cells was 5- to 15-fold higher. In serial expansion culture, a median telomeric loss of 0.7 kbp was observed during 3-4 weeks of expansion. Our results demonstrate that up-regulation of telomerase is similar in CD34+ cells from CP-CML, CLL, PV, and MDS patients and in normal hematopoietic cells during the first week of culture, whereas in AML and AP/BP-CML, telomerase is high at baseline and down-regulated during expansion culture. High levels of telomerase in leukemic progenitors at baseline may be a feature of both the malignant phenotype and rapid cycling. Telomerase down-regulation during culture of leukemic cells may be due to the decreased expansion potential or repression of normal hematopoiesis, or in AML it may be due to the partial differentiation of AML cells, shown previously to be associated with loss of TA. Telomere shortening during ex vivo expansion correlated with low levels of TA, particularly in chronic leukemic and MDS progenitors where telomerase was insufficient to protect against telomere bp loss during intense proliferation.
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PMID:Telomerase activity and telomere length in acute and chronic leukemia, pre- and post-ex vivo culture. 1067 44

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