TLR5 and graft versus host disease: High TLR5 expression has been observed in CD4+CD25+ Treg cells, and such high expression potently increases the suppressive capacity of these cells via enhanced Foxp3 expression [10]; activation of TLR5 by flagellin reduces GvHD (graft-versus-host disease) following allogeneic haematopoietic stem cell transplantation [11].