Transplantation in the onco-hematology field: focus on the manipulation of αβ and γδ T cells

gamma/delta T cells represent a subset of T cells expressing a T cell receptor (TCR) variant composed of gamma and delta chains. The gamma/delta TCR is expressed by 2-10% of all T cells in human peripheral blood, whereas the majority of T cells express alpha/beta TCRs. gamma/delta T cells display a range of innate effector functions including rapid secretion of chemokines and cytokines, as well as target cell lysis. Recent interest has focused on the function of gamma/delta T lymphocytes in allogeneic transplantation in the onco-hematology field. Several studies, in vitro and in vivo, suggest that gamma/delta T lymphocytes are potential beneficial effector cells in the context of hematopoietic stem cell transplantation (HSCT). In addition, in this review, we discuss the depletion of alpha/beta T lymphocytes in the graft for allogeneic transplantation. In fact, an efficient TCR alpha/beta cell depletion potentially reduces the risk of GvHD. Furthermore, TCR alpha/beta T cell depletion, especially with immunomagnetic negative selection, retains other potential beneficial effector cells in the graft, such as gamma/delta T cells, NK cells, and stem cells. These "facilitating" cells might facilitate engraftment, exert GvL effects, and reduce the risk for infections. (C) 2011 Elsevier GmbH. All rights reserved