In terms of regulatory cells, we identified a significantly larger number of FoxP3+ Treg (both CD4 and CD8) and CTLA4+ Treg (both CD4 and CD8) cells in the NPC group than in the HC group (p = 0.0021 [Foxp3+ Treg CD4 T], 0.0022 [Foxp3+ Treg CD8 T], <0.0001 [CTLA4+ Treg CD4 T] and 0.0062 [CTLA4+ Treg CD8 T], Figure 3A). Here, CTLA4 is linked to nasopharyngeal carcinoma.