Impaired regulatory T cell reconstitution in patients with acute graft-versus-host disease and cytomegalovirus infection after allogeneic bone marrow transplantation

To elucidate the correlation between regulatory T cells (Tregs) and acute graft-versus-host disease (aGVHD) or cytomegalovirus infection following allogeneic bone marrow transplantation (allo-BMT), we evaluated either CD4 + CD25 high or FOXP3 + Treg-enriched cells in peripheral blood (PB) from 20 patients who received allo-BMT, and in biopsies of skin with aGVHD. Proportions of CD4 + CD25 high FOXP3 + cells in total lymphocytes, but not other types of T cells, were lower in patients who eventually developed grades II–IV aGVHD ( n = 13) than in others ( n = 7, P