Regulatory CD4+CD25hi T cells conserve their function and phenotype after granulocyte colony-stimulating factor treatment in human hematopoietic stem cell transplantation.

Acute graft-versus-host disease (aGVHD), mediated by CD4(+) and CD8(+) effector T cells, is a life-threatening complication in hematopoietic stem cell transplantation. CD4(+)CD25(hi) regulatory T cells (T(reg)) have been shown to modulate tolerance to aGVHD in murine models. Based on these observations, we examined their role in the prevention of aGVHD in patients who underwent transplantation with peripheral blood-mobilized hematopoietic stem cells after administration of granulocyte colony-stimulating factor.