CD4 and cancer: Although Nrp1+ CD4+ T cells may co-express CD25 and exert regulatory function in some cancer-draining lymph nodes [24], in non-malignant lymph nodes and tonsils, Nrp1+ CD4+ T cells have a non-regulatory (CD25- FoxP3-) memory (CD45RA- CD45RO+) phenotype [25].