Therapeutic potential of CD4+ CD25+ regulatory T cells in allogeneic transplantation

The subpopulation of CD4(+) CD25(+) immunoregulatory T cells constitutes less than of the entire CD4(+) T-cell pool in mice and in humans. These cells play a crucial role in the control of autoimmune processes. More recently, in vitro and in vivo data also indicate that CD4(+) CD25(+) immunoregulatory T cells can regulate alloreactivity. This renders them good candidates for innovative strategies in the field of transplantation. Inducing a state of immune tolerance with immunoregulatory T cells would alleviate the need for immunosuppression, and the occurrence of late allograft failure represents a major goal of transplantation immunology. Here we discuss how these naturally occurring CD4(+) CD25(+) immunoregulatory T cells can be used to modulate alloreactivity in hematopoietic stem cell and solid organ transplantation.