Fig. 5.

a Frequency of CD127^loCD25^hiFoxP3⁺CD4⁺ Tregs in HPV⁺ (n = 18) and HPV⁻ (n = 14) HNSCC patients using flow cytometry analysis. Each symbol represents a patient, the horizontal line represents the average, and error bars indicate SEM. Cells are gated on CD4⁺ tumor-infiltrating T lymphocytes. b, c Correlation between Treg and pDC proportions in HPV⁺ (b) and HPV⁻ (c) HNSCC patients. Linear trendlines and p values are shown. d Columns represent the mean (± SEM) densities of FoxP3⁺ cells in tumor nests and tumor stroma of immunohistochemically stained FFPE sections of HPV⁺ (n = 12) and HPV⁻ (n = 11) HNSCC. e Colocalization of FoxP3⁺ Tregs (blue nuclei) and BDCA-2⁺ pDCs (brown membranes) in the stroma of a representative HNSCC patient. f Columns represent the average change in proportions of Tregs in pDC – CD4 + T cell co-cultures upon cultivating pDCs, derived from peripheral blood of healthy donors, with/without HPV⁺ (n = 7; black column) and HPV⁻ (n = 7; gray column) HNSCC cell culture supernatants. Error bars represent SEM. ** p < 0.01