Fig. 5.

Immune cell subsets and coregulatory molecule expression on immune cells in HPV+ vs. HPV(−) HNSCC. Protein marker expression was detected with immunohistochemistry and analyzed digitally, as detailed in “Materials and methods”. When compared to HPV(−) tumors, HPV+ tumors contained significantly higher densities of CD3+, CD4+, CD8+, CD20+, and PD-1+ cells; there was also a trend towards an increased density of FOXP3+ cells in HPV+ tumors. Expression of IDO-1 and GITR by immune cells was robust, but did not differ by tumor viral status. P-values, 2-sided Wilcoxon rank-sum test with exact distribution. Error bars display mean ± SEM