Host programmed death ligand 1 is dominant over programmed death ligand 2 expression in regulating graft-versus-host disease lethality

Key Points PD-L1 and PD-L2 expression were upregulated during GVHD, whereas PD-1/PD-L1 was more critical than PD-1/PD-L2 in downregulating GVHD. Our data provide new insight into the differential roles of host PD-L1 and PD-L2 and associated mechanisms in controlling GVHD.