title: Low-dose total body irradiation causes clonal fluctuation of primate hematopoietic stem and progenitor cells.
abstract: Due to high frequency of side effects caused by high-dose total body irradiation (TBI) the nonmyeloablative regimen together with cytotoxic agents is currently used especially for elderly patients. However, immediate and long-term effects of low-dose irradiation used in allogeneic transplantation on stem cells is less well known. We have studied the effect of low-dose 3 Gy TBI on the number of hematopoietic stem cell (HSC) clones contributing simultaneously to granulocyte production in rhesus macaque. The number of clones after 3 Gy TBI decreased markedly by 2 to 3 weeks after 3 Gy TBI, followed by a period of clonal instability, and recovery to almost pre-3 Gy TBI clonal diversity. The clones accounting for this recovery contributed before 3 Gy TBI, suggesting the profound initial impact of TBI was on a pool of progenitor cells, whereas most of the more primitive HSCs remained unaffected and were able to again contribute to hematopoiesis after recovery. Clonal fluctuation may indirectly suggest the presence of short-term/long-term HSC populations in rhesus macaque bone marrow as reported in a mouse model. The results indicate that even low-dose irradiation affects hematopoietic clonal dynamics and have implications for design of conditioning regimens for transplantation purposes.
authors.affiliation: Molecular Hematopoiesis Section, Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bldg 10, Rm 7C103, 9000 Rockville Pike, Bethesda, MD 20892, USA.
authors.forename: Mikko O
authors.initials: MO
authors.lastname: Laukkanen
authors.forename: Ken
authors.initials: K
authors.lastname: Kuramoto
authors.forename: Boris
authors.initials: B
authors.lastname: Calmels
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takatoku
authors.forename: Christof
authors.initials: C
authors.lastname: von Kalle
authors.forename: Robert E
authors.initials: RE
authors.lastname: Donahue
authors.forename: Cynthia E
authors.initials: CE
authors.lastname: Dunbar
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000528:radiation effects; D003001:Cloning, Molecular; D017931:DNA Primers; D006098:Granulocytes / Q000166:cytology / Q000528:radiation effects; D006412:Hematopoietic Stem Cells / Q000528:radiation effects*; D008253:Macaca mulatta / Q000097:blood*; D023421:Models, Animal; D016133:Polymerase Chain Reaction; D013234:Stem Cells / Q000528:radiation effects*; D014916:Whole-Body Irradiation
chemical_list: D017931:DNA Primers