CCL23, a chemokine involved in the recruitment of macrophages, has also been demonstrated to be considerably up-regulated in CRSwNP tissue, suggesting that macrophages might be recruited into nasal polyps by CCL23, and the presence of Th2 cytokines subsequently results in skewing toward the M2 phenotype [185]. Here, CCL23 is linked to chronic rhinosinusitis with nasal polyps.