In cardiac transplantation studies, high levels of LILRB4 expression on circulating Ts cell-induced APCs in peripheral blood were associated with a significant reduction in rejection [60].Transplanting splenocytes from heterozygous C57 LILRB4(-/-) mice into BALB/C mice did not cause severe graft-versus-host disease, indicating the crucial role of LILRB4 in inducing immune tolerance post-transplantation [96]. Here, LILRB4 is linked to graft versus host disease.