IL33 and chronic obstructive pulmonary disease: Furthermore, IL-33 induces and enhances the secretion of IL-6 and IL-8 in human bronchial epithelial cells (HBEs) and peripheral blood mononuclear cells (PBMCs) from COPD patients via the IL-1 family receptor accessory protein (IL-1RAcP) and MAPK pathways, perpetuating chronic inflammation in the respiratory tract (45).