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Involvement and functional impairment of the CD34(+)CD38(-)Thy-1(+) hematopoietic stem cell pool in myelodysplastic syndromes with trisomy 8.

Author

  • Lars Nilsson
  • Ingbritt Åstrand-Grundström
  • Kristina Anderson
  • Ingrid Arvidsson
  • Peter Hokland
  • David Bryder
  • Lars Kjeldsen
  • Bertil Johansson
  • Eva Hellström-Lindberg
  • Robert Hast
  • Sten Eirik W Jacobsen

Summary, in English

Clonality studies of mature cells suggest that the primary transformation event in myelodysplastic syndrome (MDS) most frequently occurs in a myeloid-restricted progenitor, a hypothesis supported by recent studies of purified CD34(+)Thy1(+) hematopoietic stem cells (HSCs) in cases with trisomy 8 (+8). In contrast, we recently demonstrated that a lymphomyeloid HSC is the target for transformation in MDS cases with del(5q), potentially reflecting heterogeneity within MDS. However, since +8 is known to frequently be a late event in the MDS transformation process, it remained a possibility that CD34(+)CD38(-)Thy1(+) HSC disomic for chromosome 8 might be part of the MDS clone. In the present studies, although a variable fraction of CD34(+)CD38(-)Thy1(+) cells were disomic for chromosome 8, they did not possess normal HSC activity in long-term cultures and nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice. Mixing experiments with normal CD34(+)CD38(-) cells suggested that this HSC deficiency was intrinsic and not mediated by indirect mechanisms. Furthermore, investigation of 4 MDS cases with combined del(5q) and +8 demonstrated that the +8 aberration was always secondary to del(5q). Whereas del(5q) invariably occurs in CD34(+)CD38(-)Thy-1(+) HSCs, the secondary +8 event might frequently arise in progeny of MDS HSCs. Thus, CD34(+)CD38(-)Thy1(+) HSCs are invariably part of the MDS clone also in +8 patients, and little HSC activity can be recovered from the CD34(+) CD38(-)Thy1(+) HSC. Finally, in advanced cases of MDS, the MDS reconstituting activity is exclusively derived from the minor CD34(+)CD38(-) HSC population, demonstrating that MDS stem cells have a similar phenotype as normal HSCs, potentially complicating the development of autologous transplantation for MDS.

Topic

  • Hematology

Keywords

  • Male
  • Human
  • Hematopoietic Stem Cells : pathology
  • Hematopoietic Stem Cells : immunology
  • Female
  • Clone Cells : pathology
  • Clone Cells : immunology
  • Pair 8
  • Chromosomes
  • Neoplastic : pathology
  • Cell Transformation
  • Neoplastic : genetics
  • Thy-1 : analysis
  • Antigens
  • Differentiation : analysis
  • CD34 : analysis
  • 80 and over
  • Aged
  • Middle Age
  • Myelodysplastic Syndromes : etiology
  • Myelodysplastic Syndromes : genetics
  • Myelodysplastic Syndromes : pathology
  • NAD+ Nucleosidase : analysis
  • Support
  • Non-U.S. Gov't
  • Trisomy
  • Tumor Stem Cells : immunology
  • Tumor Stem Cells : pathology

Status

Published

ISBN/ISSN/Other

  • ISSN: 1528-0020