Our data showed that BTLA expressions were significantly upregulated while HVEM expression remained unchanged on circulating CD4+ T cells in HCC patients compared to that in healthy donors (Figures 1(a) and 2(a)), providing an increase of inhibitory signaling through BTLA engaged by intercellular HVEM in trans. Second, BTLA could interact with HVEM in cis on T cells in which both BTLA and HVEM are expressed, which alleviate coinhibitory signaling by BTLA [26, 27]. Here, CD4 is linked to hepatocellular carcinoma.