[T-Cell Regeneration after Allogeneic Hematopoietic Stem Cell Transplantation and Its Significance]

Allogeneic hematopoietic stem cell transplantation is curative therapy for many malignant hematologic and genetic disorders. The pathways by which T cell are regenerated in vivo are of central importance for host immune competence after the transplantation. Thymic-dependent and thymic-independent pathways of T-cell regeneration are primarily determined by thymus function, and that thymic-independent pathways are generally inadequate for restoration of host immunocompetence. T cell regeneration of adult recipients is largely through thymic-independent pathways due to reduced thymic regeneration capacity, resulting in quantitative defficiencies in T-cell number and severe restriction in the diversity of the regenerated T-cell receptor (TCR) repertoire. New strategies to enhance thymic function in man after BMT would hold great therapeutic potential. Activation of donor T cells is the cause of GVHD, the induction of anergy can inactivate specific sets of alloreactive T cells in the donor stem cells, which can prevent GVHD without inhibiting the entire T-cell repertoire.