We previously evaluated the association of CD161-expressing T cells with the development of acute graft-versus-host disease after allogeneic SCT and found that a low proportion of CD8+CD161+ cells and a high ratio of CD4+CD161+ cells to CD8+CD161+ cells from peripheral blood at engraftment were associated with the occurrence of acute graft-versus-host disease, with evidence of higher expression of the Th17 transcription factor RORγT in CD4+CD161+ T cells rather than CD8+CD161+ T cells [30]. This evidence concerns the gene KLRB1 and acute graft versus host disease.