IL4 and Nasal polyposis: Wang et.al identified PD-1hiCXCR5−CD4+ T cells in nasal polyps that can be characterized by expression of IFN-γ, IL-17A, and IL-4, and PD-1hiCXCR5−CD4+ T cells can induce IgE production via IL-4 only in eosinophilic NPs [107].