CD4 and graft versus host disease: Conversely, mice receiving WT-CD4 with Lag-3−/−CD8 T cells had less severe GVHD and showed significant increase in median survival (P = 0.02) when compared with mice receiving Lag-3−/−Tcon, suggesting that Lag-3 engagement on CD8 T cells has a smaller influence on limiting the alloreactive T cell response after BMT.