As indicated in Fig. 2G, mice receiving Lag-3−/−CD4 with WT-CD8 T cells showed similar survival and GVHD symptoms as mice receiving both Lag-3−/− CD4 and CD8 T cells suggesting that the absence of Lag-3 on CD4 T cells is responsible for the observed increased GVHD pathogenesis. Here, LAG3 is linked to graft versus host disease.