CD4 and head and neck squamous cell carcinoma: A decrease in the number of CD4+ T lymphocytes increases the risk of having an oral HPV infection and developing malignancy [68, 71, 78, 79, 82, 91, 92, 94], while the number of CD8+ T lymphocytes does not seem to be associated with the incidence of HPV-related HNSCC [79].