CD8A and graft versus host disease: Notably, the expression pattern of PD-1 and TOX in TCF1+ and TCF1- CD8+ T cells during acute GvHD was the opposite between 7 and 28 dpt (Figs. 1E, H, and Supplementary Fig. 5), and this phenomenon was also observed in chronically infected mice (Figs. 1E, H, and Supplementary Fig. 6).