FAS and cirrhosis of liver: Changes of expression of co-stimulatory molecules and T cell activation markers were accompanied by a significant upregulation of the Fas-receptor CD95 on CD4+ T cells and CD8+ T cells (Figures 4A–6A), which promotes T cell apoptosis, as well as by an increased expression of inhibitory immune checkpoints, namely PDPN, KLGR1, PROCR, and 2B4 on CD4+ effector T cells, CD4+ regulatory T cells and CD8+ T cells, whereas upregulation of the inhibitory immune checkpoints PD-1, CTLA4, BTLA, TIM-3, LAG-3, and TIGIT in patients with liver cirrhosis was more variable (Figures 4B–6B).