[CD4+CD25+ regulatory T cells and their function in graft-versus-host disease--review]

As a functionally and phenotypically distinctive T cell subpopulation, CD4+CD25+ regulatory T cells are anergic and retain their ability to suppress antigen-driven response of CD4+CD25- cells in a contact-dependent manner or through a way of secreting immunosuppressive cytokines such as IL-10 and TGF-beta. Graft-versus-host disease (GVHD) is one of the major complications following allogeneic hematopoietic stem cell transplantation (HSCT). Recently, some researches on the relationship between donor CD4+CD25+ regulatory T cells and GVHD severity produced two contradictory conclusions: one is CD4+CD25+ regulatory T cells that can prevent GVHD efficiently; the other is that GVHD is associated with the increased numbers of peripheral blood CD4+CD25+ regulatory T cells. The answer to this question will provide a new idea for clinic therapy of GVHD. In this review some new research progresses in the related area, such as the CD4+CD25+ regulatory T cells, the phenotype, characteristics, immunoregulatory mechanisms of CD4+CD25+ regulatory T cells, as well as the relation of CD4+CD25+ with GVHD were presented.