Fig. 4
From: Age-related changes in T lymphocytes of patients with head and neck squamous cell carcinoma
PD1 expression on T cell subtypes. The expression levels of PD1 on CD8+ T cells (a), CD4+ T cells (b) and Treg (c) in the different groups were plotted. The trend of the expression of PD1 on CD8+ T cells (d) and CD4+ T cells (e), as well as for Treg (f) for both healthy and tumor blood volunteers was depicted. P < 0.05 (*); p < 0.01 (**)