ABSTRACT
Allogeneic hematopoietic stem cell transplantation is associated with several complications and risk factors, for example, graft versus host disease (GVHD), viral infections, relapse, and graft rejection. While high levels of CD3+ cells in grafts can contribute to GVHD, they also promote the graft versus leukemia (GVL) effect. Infusions of extra lymphocytes from the original stem cell donor can be used as a treatment after transplantation for relapse or poor immune reconstitution but also they increase the risk for GVHD. In peripheral blood, 95% of T-cells express the αß T-cell receptor and the remaining T-cells express the γδ T-cell receptor. As αß T-cells are the primary mediators of GVHD, depleting them from the graft should reduce this risk. In this pilot study, five patients transplanted with HLA-matched related and unrelated donors were treated with αß T-cell depleted stem cell boosts. The majority of γδ T-cells in the grafts expressed Vδ2 and/or Vγ9. Most patients receiving αß-depleted stem cell boosts increased their levels of white blood cells, platelets, and/or granulocytes 30 days after infusion. No signs of GVHD or other side effects were detected. A larger pool of patients with longer follow-up time is needed to confirm the data in this study.
Subject(s)
Graft Rejection/immunology , Hematopoietic Stem Cell Transplantation/methods , Receptors, Antigen, T-Cell, alpha-beta/immunology , T-Lymphocytes/immunology , Adult , Blood Cell Count , Child, Preschool , Female , Flow Cytometry , Graft Rejection/etiology , Graft Rejection/metabolism , Graft vs Host Disease/etiology , Graft vs Host Disease/immunology , Graft vs Host Disease/metabolism , Hematopoietic Stem Cell Transplantation/adverse effects , Histocompatibility Testing , Humans , Lymphocyte Depletion , Male , Middle Aged , Pilot Projects , Polymerase Chain Reaction , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Receptors, Antigen, T-Cell, gamma-delta/genetics , Receptors, Antigen, T-Cell, gamma-delta/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolism , T-Lymphocytes/metabolism , Time Factors , Transplantation, Homologous , Treatment Outcome , Unrelated Donors , Young AdultABSTRACT
INTRODUCTION: Despite routine use of umbilical cord blood (CB) grafts as stem cell source for allogeneic stem cell transplantations, much remains unknown regarding their cell composition and correlation with clinical outcome. METHODS: We analyzed material from 30 CB units used for allogeneic hematopoietic stem cell transplantation by multicolor flow cytometry. Phenotypic data were correlated with various clinical outcomes such as survival, graft-versus-host disease (GVHD), relapse, rejection, viral reactivation, and bacteremia. RESULTS: We found that above-median frequencies of CD69+ T cells, naïve CD8+ T cells, and CD127+ B cells in the CB graft were each associated with significantly improved patient survival. Moreover, a statistically significant correlation was seen between higher levels of CD94+ T cells and herpes simplex virus and varicella zoster virus reactivation post transplantation. A similar correlation was seen for the frequency of CD95+ cells in total CD3+, as well as CD4+ and CD8+ T-cell subsets, and viral reactivation. Finally, a higher frequency of naïve CD8+ T cells was associated with the incidence of acute GVHD. CONCLUSION: Our study highlights the importance of further exploration of graft composition before CB transplantation as a tool for risk prediction.
