Thus, administration of tolerogenic anti-IL-2 that specifically blocks IL-2Rβ signaling may represent a novel approach for preventing aGVHD while preserving strong GVL activity through the expansion of functional CD8+ T cells in lymphoid organs while inducing Tcon anergy/exhaustion in GVHD target tissues (Figure 1). The gene discussed is CD8A; the disease is graft versus host disease.