Boccadoro, Mario

Bruno, Benedetto

Christian, Scharenberg

Eleonora, Marzanati

Elona, Saraci

Eva Hellstr&#246

Ferrero, Dario

Giai, Valentina

Palumbo, Antonio

Paola, Omed&#232

English

Institutional Research Information System University of Turin

EBMT 2015 - Physicians Abstract (including Data and QualityManagement)Topic area: General TopicsTopic: 06. Stem cell mobilisation and Graft engineeringEBMT15-ABS-2481Hematopoietic stem and progenitor cell composition in peripheral blood and in mobilized CD34+ cells harvests.Valentina Giai* 1, Elona Saraci1, Eleonora Marzanati1, Christian Scharenberg2, Paola Omedè1, Eva Hellström-Lindberg2,Antonio Palumbo1, Benedetto Bruno1, Mario Boccadoro1, Dario Ferrero11Division of Hematology, University of Torino, Torino, Italy, 2Center for Hematology and Regenerative Medicine,Karolinska University Hospital, Stockholm, SwedenPreferred Method of Presentation: Oral or Poster PresentationIntroduction: Hematopoietic stem cell transplantation is a procedure now well established, although optimal outcomesare not always achieved. Nowadays, mobilized peripheral CD34+ cells are the preferred source of hematopoietic stemand progenitor cells for transplantation purposes. Unfortunately, very little is known about the peripheral CD34+ cellscomposition in terms of committed myeloid progenitors and stem cells. In the present study, we intend to investigate theproportions of hematopoietic progenitors and stem cells available in mobilized peripheral blood (PB) and correlate thiswith clinical information and outcomes of patients who underwent a transplantation procedure. Materials (or patients) and methods: Multicolor flow-cytometry was used to analyze CD34+ cells from 4 bone marrow(BM) samples and 9 PB samples from healthy volunteers and 32 mobilized PB samples from hematological patients priorCD34+ cell harvesting. Results: RESULTS: Common myeloid progenitors (CMP) were present in a higher percentage in PB compared to BM(47.8% ± 9.5 versus 27.6% ± 9.5 of CD34+ cells) while granulocyte-macrophage progenitors (GMP) were lower in PBcompared to BM (10.3% ± 6.9 versus 23.8% ± 7.2). No significant differences were noticed between PB and BMhematopoietic stem cells (HSC). According to literature, progenitor fractions were equally distributed in BM (27.6% ± 9.5CMP, 23.8% ± 7.2 GMP and 27.6% ± 16.2 megakaryocyte-erythroid progenitors, MEP). No differences in subpopulationsfractions were shown between baseline and mobilized CD34+ cells. Concerning the two samples mobilized with theCXCR4 inhibitor Plerixafor instead of G-CSF only, we noticed that a more elevated ratio of GMP were released in PB:37.8% in patient#1 and 33.8% in patient#2 compared to the average 16.31% of “G-CSF only” mobilized samples.Analyzing CXCR4 levels among subpopulations of both mobilized or unmobilized samples, it was more expressed onGMP than on the other CD34+ cell subsets.A strong correlation was observed between the number of peripheral CD34+ cells and the number of circulating CMPwhose proportion did not change with increasing CD34+ cell release. White blood cells (WBC) count exhibited asignificant correlation with the number of mobilized HSC; on the contrary, WBC, hemoglobin and platelet levels did notshow correlations with the number of mobilized CMP/GMP/MEP.We then looked at possible relationships between the number of re-infused subpopulations and the hematologicalrecovery after an auto-transplantation conditioned by high dose chemotherapy. A tendency to inverse correlation wasshown between the number of re-infused progenitors and the days of aplasia, as well as between the number of re-infused MEP and erythrocyte/platelet transfusions. However, these results did not reach a statistical significance,probably for the too low patient number.Conclusion: CD34+ cell subset composition shows differences between BM and PB. We do not know yet if variabilities inthe proportions of different progenitor/stem cell re-infused can influence clinical issues such as infections complicationsand transfusion requirement in patient undergoing an hematopoietic stem cell transplantation. A deep understanding ofthese mechanisms may guide the clinician in the choice of the most suitable chemotherapy or mobilizing regimen andlead up to an improved clinical outcomes of such patients. Disclosure of Interest: None DeclaredKeywords: CD34+ cells, Hematopoietic Stem Cells, peripheral blood stem cell, stem cell mobilization

Hematopoietic stem and progenitor cell composition in peripheral blood and in mobilized CD34+ cells harvests.

https://iris.unito.it/bitstream/2318/1507554/1/EBMT15-ABS-2481-preview-1.pdf

Hematopoietic stem and progenitor cell composition in peripheral blood and in mobilized CD34+ cells harvests.

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