Mesenchymal stem cells remain host-derived independent of the source of the stem-cell graft and conditioning regimen used.
BACKGROUND
Human bone marrow contains hematopoietic stem cells and stroma cells known as mesenchymal stem cells (MSC). MSC are cells with the morphological features of fibroblasts, which, in addition to their nursing function for hematopoietic stem cells, retain the ability to differentiate into cartilage, bone, fat, muscle, and tendon and have an important immunmodulatory function. To understand in more detail hematopoietic engraftment and immune modulation after hematopoietic cell transplantation, we investigated the ability of donor MSC to engraft after hematopoietic cell transplantation in dependency to the conditioning regimen (myeloablative vs. reduced intensity) and source of the graft (bone marrow vs. peripheral blood).


METHODS
Bone marrow MSC of 12 patients were analyzed, a median of 23.4 (range 0.9-137.8) months after human leukocyte antigen matched but gender mismatched bone marrow transplantation after myeloablative conditioning (n=4) or peripheral blood cell transplantation after myeloablative (n=4) or reduced intensity conditioning (n=4). MSC were characterized by morphology, positivity for CD 105+, CD73+, CD 44+, and CD 90+, and by their capacity to differentiate into adipocytic and osteogenic cells. Recipient and donor origins were determined by fluorescent in situ hybridization for sex chromosomes.


RESULTS
While overall blood and bone marrow chimerism was 100% donor type, MSC remained in all patients of recipient origin (>96%). There was no difference between patients receiving bone marrow and peripheral blood grafts, nor was any difference observed between patients receiving full intensity in comparison with reduced intensity conditioning.


CONCLUSIONS
We conclude that MSC remain of host type irrespective of the conditioning regimen and graft source.
Bartsch
Kristina
K
Department of Hematology and Oncology, University of Leipzig, Leipzig, Germany. Kristina.Bartsch@medizin.uni-leipzig.de
Al-Ali
Haifa
H
Reinhardt
Annette
A
Franke
Christina
C
Hudecek
Michael
M
Kamprad
Manja
M
Tschiedel
Sabine
S
Cross
Michael
M
Niederwieser
Dietger
D
Gentilini
Chiara
C
D000328:Adult; D053687:Adult Stem Cells / Q000187:drug effects* / Q000276:immunology; D016026:Bone Marrow Transplantation; D018929:Cell Culture Techniques; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D005260:Female; D006650:Histocompatibility Testing; D006801:Humans; D016130:Immunophenotyping; D007938:Leukemia / Q000276:immunology / Q000601:surgery*; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology / Q000601:surgery*; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000276:immunology; D008875:Middle Aged; D019653:Myeloablative Agonists / Q000627:therapeutic use*; D013997:Time Factors; D018183:Transplantation Chimera; D019172:Transplantation Conditioning / Q000379:methods*; D014184:Transplantation, Homologous; D055815:Young Adult
D019653:Myeloablative Agonists