GRANULOCYTE-COLONY-STIMULATING FACTOR MOBILIZES INTO PERIPHERAL-BLOODTHE COMPLETE CLONAL REPERTOIRE OF HEMATOPOIETIC PRECURSORS RESIDING IN THE BONE-MARROW OF MICE

We have established the clonal relationships between the hematopoietic precursors residing in the bone marrow (BM) and the peripheral blood (PB) of mice treated with granulocyte colony-stimulating factor (G-CSF ). The use of animals whose hematopoiesis was reconstituted with genet ically labeled stem cells has allowed us to show that an almost identi cal repertoire of clones is found in the colony-forming unit (CFU-S) p opulation present in the BM and mobilized PB. Moreover, our data has s hown that the frequency of expression of the repopulating clones in bo th types of CFUS populations is the same, evidencing that G-CSF mobili zed PB progenitor cells (PBPCs) closely reflect the clonal makeup of t he hematopoietic precursors residing in the BM. When secondary recipie nts were transplanted with BM or mobilized PB grafts that had been har vested from the genetically marked mice, the presence of long-term lym pho-hematopoietic repopulating clones was showed not only in the BM bu t also in the PB samples. No new clones were identified in the long-te rm repopulating cells of the mobilized animals with respect to those f ound in the CFU-S population. Moreover, the hematopoietic precursors t hat were capable of long-term reconstitution corresponded to the clone s, which were most highly represented in the CFU-S compartment, sugges ting, at least in the case of G-CSF treated mice, that the frequency o f expression of the repopulating clones in the CFU-S population is pro gnostic for the clone longevity. Based on our experimental data, new a dvantages for the use of mobilized PBPCs in place of hematopoietic gra fts procured from limited areas of BM are proposed. (C) 1996 by The Am erican Society of Hematology.