title: Mesenchymal stem cells remain of host origin even a long time after allogeneic peripheral blood stem cell or bone marrow transplantation.
abstract: OBJECTIVE
  Plasticity of hematopoietic stem cells (HSC) has gained major interest in stem cell research. In order to investigate whether HSC may differentiate into mesenchymal stem cells (MSC), we assessed chimerism in peripheral blood (PB), mononuclear cell fractions (MNC) of bone marrow, and MSC derived from bone marrow (BM) from 27 up to 4225 days after allogeneic transplantation.
  
  
  METHODS
  We applied fluorescence in situ hybridization using X/Y gene probes in sex-mismatched and STR-PCR in sex-matched patients. MSC could have been generated in 27 of 55 bone marrow samples derived from 20 patients. Fifteen patients received peripheral blood stem cell transplants (PBSCT), including CD34-selected PBSCT in two. Five patients received bone marrow.
  
  
  RESULTS
  While all patients had chimerism in PB and MNC of the BM, in all but one patient BM-derived MSC were of recipient origin. This single patient showed reproducibly MSC of donor origin in a frequency of 1% after having received a CD34-selected PBSCT. Looking at graft collections, MSCs were easily generated from BM specimens, while no MSC could be derived from PBSC samples.
  
  
  CONCLUSIONS
  Even though HSC have been found to differentiate into a variety of nonhematological cell types, they usually do not differentiate into MSC after allogeneic transplantation.
authors.affiliation: Department of Hematology, Oncology and Transfusion Medicine, Charité-Campus Benjamin Franklin, University School of Medicine, Berlin, Germany. kathrin.rieger@charite.de
authors.forename: Kathrin
authors.initials: K
authors.lastname: Rieger
authors.forename: Olga
authors.initials: O
authors.lastname: Marinets
authors.forename: Thomas
authors.initials: T
authors.lastname: Fietz
authors.forename: Sixten
authors.initials: S
authors.lastname: Körper
authors.forename: Dagmar
authors.initials: D
authors.lastname: Sommer
authors.forename: Carola
authors.initials: C
authors.lastname: Mücke
authors.forename: Birgit
authors.initials: B
authors.lastname: Reufi
authors.forename: Wolfgang I
authors.initials: WI
authors.lastname: Blau
authors.forename: Eckhard
authors.initials: E
authors.lastname: Thiel
authors.forename: Wolfgang U
authors.initials: WU
authors.lastname: Knauf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016026:Bone Marrow Transplantation; D005260:Female; D019337:Hematologic Neoplasms / Q000601:surgery*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008648:Mesoderm / Q000166:cytology*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology*; D014184:Transplantation, Homologous