title: Mesenchymal stem cells are present in peripheral blood and can engraft after allogeneic hematopoietic stem cell transplantation.
abstract: OBJECTIVE
  Whether human mesenchymal stem cells (MSC) can be transplanted is controversial and their presence in peripheral blood is not fully accepted. In the present study we have analyzed whether, within the allogeneic transplantation setting, MSC are of host or donor origin.
  
  
  METHODS
  Bone marrow MSC from 19 patients who had undergone allogeneic transplantation were expanded and identified using immunophenotypic markers. After that, chimerism studies were performed using reverse transcription polymerase chain reaction of short tandem repeat (STR) loci. Analyses were carried out at different time-points after transplantation, with a total of 44 samples studied. Bone marrow was used as the source of stem cells for transplantation in 4 cases and peripheral blood in 15 cases. The conditioning regimen was standard in 9 patients and non-myeloablative in 10 patients.
  
  
  RESULTS
  Our results show that in the great majority of cases analyzed (17 out 19), MSC were of host origin. However, in 2 patients with multiple myeloma who had received a reduced intensity transplantation using peripheral blood stem cells, MSC were partially of donor origin (60.17% and 26.13% of total MSC).
  
  
  CONCLUSIONS
  These findings indicate that after allogeneic transplantation MSC from the donor can engraft in bone marrow. Moreover, since the stem cells were obtained from peripheral blood, it can be concluded that MSC circulate among mobilized peripheral blood stem cells and can engraft in bone marrow after allogeneic transplantation.
authors.affiliation: Hematology Dept., Hospital Universitario de Salamanca, Paseo San Vicente 58-182, 37007 Salamanca, Spain.
authors.forename: Eva María
authors.initials: EM
authors.lastname: Villaron
authors.forename: Julia
authors.initials: J
authors.lastname: Almeida
authors.forename: Natalia
authors.initials: N
authors.lastname: López-Holgado
authors.forename: Miguel
authors.initials: M
authors.lastname: Alcoceba
authors.forename: Luis Ignacio
authors.initials: LI
authors.lastname: Sánchez-Abarca
authors.forename: Fermin Martin
authors.initials: FM
authors.lastname: Sanchez-Guijo
authors.forename: Mercedes
authors.initials: M
authors.lastname: Alberca
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Pérez-Simon
authors.forename: Jesus Fernando
authors.initials: JF
authors.lastname: San Miguel
authors.forename: María Consuelo
authors.initials: MC
authors.lastname: Del Cañizo
mesh_terms: D017667:Adipocytes / Q000166:cytology; D001773:Blood Cells / Q000145:classification / Q000166:cytology*; D001854:Bone Marrow Cells / Q000166:cytology; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured / Q000166:cytology; D006085:Graft Survival; D019337:Hematologic Neoplasms / Q000097:blood / Q000628:therapy; D006801:Humans; D016130:Immunophenotyping; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D009101:Multiple Myeloma / Q000097:blood / Q000628:therapy; D010006:Osteoblasts / Q000166:cytology; D036102:Peripheral Blood Stem Cell Transplantation; D018183:Transplantation Chimera; D019172:Transplantation Conditioning; D014184:Transplantation, Homologous