Interestingly, there is also high expression of TIGIT in allogeneic hematopoietic stem cell transplantation and CD8+ T cells from acute myeloid leukemia (AML) patients, where it may mitigate the severity of graft-versus-host disease (GVHD) and is associates with primary refractory disease and leukemia relapse post transplantation (144–146). The gene discussed is CD8A; the disease is graft versus host disease.