title: Primitive hematopoietic stem cells shows a polyclonal pattern in myelodysplastic syndromes.
abstract: OBJECTIVE
  Clonal hematopoiesis is the hallmark of myelodysplastic syndromes, but the role played by pluripotent stem cells and progenitor cells in these disorders remains unclear.
  
  
  METHODS
  Eight female patients with myelodysplastic syndrome were studied. X-chromosome inactivation patterns were analyzed in peripheral blood granulocytes, T-lymphocytes, single colonies originating from bone marrow progenitors and pluripotent stem cells, using the human androgen receptor locus polymorphism assay.
  
  
  RESULTS
  Granulocytes and progenitor cells were monoclonal in 7/8 cases. Immature stem cells showed a non-clonal pattern of X-inactivation and were detectable at diagnosis in the presence of clonal hematopoiesis. T-lymphocyte clonality was heterogeneous.
  
  
  CONCLUSIONS
  In myelodysplastic syndromes, hematopoiesis may be dominated by a neoplastic clone by virtue of its biological advantage over a residual polyclonal, probably still normal, population of immature stem cells still able to grow in vitro.
authors.affiliation: Department of Medical Science, University of Piemonte Orientale Amedeo Avogadro Novara, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Guidetti
authors.forename: Sandra
authors.initials: S
authors.lastname: Grazioli
authors.forename: Francesca
authors.initials: F
authors.lastname: Capelli
authors.forename: Claudia
authors.initials: C
authors.lastname: Marini
authors.forename: Margherita
authors.initials: M
authors.lastname: Gallicchio
authors.forename: Daniela
authors.initials: D
authors.lastname: De Micheli
authors.forename: Luigi
authors.initials: L
authors.lastname: Castello
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Sainaghi
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Fra
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Saglio
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Avanzi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000753:Anemia, Refractory / Q000235:genetics / Q000473:pathology; D000754:Anemia, Refractory, with Excess of Blasts / Q000235:genetics / Q000473:pathology; D001854:Bone Marrow Cells / Q000473:pathology; D018929:Cell Culture Techniques; D041321:Chromosomes, Human, X / Q000235:genetics; D002999:Clone Cells / Q000473:pathology*; D019175:DNA Methylation; D004303:Dosage Compensation, Genetic; D005260:Female; D006412:Hematopoietic Stem Cells / Q000473:pathology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000473:pathology; D009190:Myelodysplastic Syndromes / Q000235:genetics / Q000473:pathology*; D009504:Neutrophils / Q000473:pathology; D010641:Phenotype; D039904:Pluripotent Stem Cells / Q000473:pathology; D013234:Stem Cells / Q000473:pathology