Mesenchymal stem cells remain of host origin even a long time after allogeneic peripheral blood stem cell or bone marrow transplantation.
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.
Rieger
Kathrin
K
Department of Hematology, Oncology and Transfusion Medicine, Charité-Campus Benjamin Franklin, University School of Medicine, Berlin, Germany. kathrin.rieger@charite.de
Marinets
Olga
O
Fietz
Thomas
T
Körper
Sixten
S
Sommer
Dagmar
D
Mücke
Carola
C
Reufi
Birgit
B
Blau
Wolfgang I
WI
Thiel
Eckhard
E
Knauf
Wolfgang U
WU
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