RESUMO
BACKGROUND: Cord Blood (CB) are increasingly used as an alternative stem cells source in adults for allogeneic Stem Cell Transplantation (allo-SCT). The risk of human herpesvirus (HHV-6) reactivation is significantly higher after CB transplant vs unrelated peripheral blood stem cells (PBSC) allo-SCT. Higher HHV-6 cell receptor CD46 expression on progenitor cells in CB may explain this difference. OBJECTIVES: To prospectively compare the HHV-6 cell receptor CD46 expression on various cell subsets of three freshly harvested blood sources on one hand and of three graft sources on the other hand. STUDY DESIGN: 52 samples were used for the purpose of this study. They were issued from peripheral blood (PB, n = 10), G-CSF mobilised PB (GCSF-PB, n = 10), cord blood (CB, n = 10), unmanipulated bone marrow (uBM, n = 5), leukapheresis product (LP, n = 10) and thawed CB graft (n = 7). CD46 expression was assessed by FACS analysis on total lymphocytes, monocytes, NK cells, T and B cells subsets, plasmacytoid (pDCs) dendritic cells and stem cells. RESULTS: As all cell subsets were found CD46 positive, CD46 mean fluorescence intensity (MFI) was then considered for comparison between the three blood sources and the three graft sources. The most impressive result observed was that HHV-6 cell receptor CD46 expression was significantly reduced in almost all cell components of thawed CB graft compared to other graft sources. CONCLUSIONS: This original study shows strong differences in term of quantitative CD46 expression between several blood and grafts samples. Our results suggest that other factors than the qualitative CD46 expression play a role in the higher HHV-6 reactivation observed after CB transplant in adults.
Assuntos
Sangue Fetal/citologia , Herpesvirus Humano 6 , Proteína Cofatora de Membrana/metabolismo , Receptores Virais/metabolismo , Ativação Viral , Adulto , Idoso , Linfócitos B/citologia , Linfócitos B/virologia , Células Dendríticas/citologia , Células Dendríticas/virologia , Feminino , Citometria de Fluxo , Imunofluorescência , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/virologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Transplante Homólogo , Adulto JovemRESUMO
BACKGROUND: Studies comparing cell components of blood and graft sources are very scarce. We present here a thorough study examining the cellular content of various sources of blood and cell therapy products. STUDY DESIGN AND METHODS: We have prospectively compared by fluorescence-activated cell sorting analyses the cellular composition of three blood sources on the one hand--peripheral blood (PB; n = 10) versus granulocyte-colony-stimulating factor (G-CSF)-mobilized PB (GCSF-PB, n = 10) versus cord blood (CB, n = 10)--and of three graft sources on the other hand--unmanipulated bone marrow (uBM, n = 5) versus leukapheresis product (LP, n = 10) versus thawed CB graft (n = 7). RESULTS: All median absolute numbers of cell subsets were found significantly higher in GCSF-PB and LP, except for monocytoid dendritic cells (mDCs) in CB and uBM. The most impressive results were the median quantities of memory T and B lymphocytes but also of plasmacytoid DCs (pDCs) contained in LP compared to thawed CB graft, with ratios of 375, 318, and 247, respectively. The proportions of naive and CD4+/CD8- T cells, transitional B cells, and CD5+ and naive B lymphocytes were found significantly higher in CB samples while the proportions of mDCs and pDCs were found significantly lower. CONCLUSION: Our study shows strong differences in terms of quantitative and qualitative cellular composition between several blood or graft sources, possibly explaining the differences observed in terms of outcomes after transplant.