In vivo inhibition of GVHD mortality by the co-infusion of tolerized cells. Tolerized cells reduce GVHD mortality induced by naive cells. One hundred thousand naive B6 CD4⁺ T cells were injected with or without 10⁵ tolerized B6 CD4⁺ T cells into sublethally irradiated bm12 recipients. Three separate experiments were pooled; n = 24 for recipients of naive cells and n = 23 for recipients of naive and tolerized cells (P < .001). Also shown is long-term survival of all recipients of tolerized cells alone (n = 23). On the x-axis are days after transfer of T cells. The y-axis shows the proportion of recipients surviving after transfer.