CXCL8 and airway hyperresponsiveness: In addition to its ability to stimulate neutrophil recruitment, IL-8 may contribute to the pathogenesis of severe asthma by directly facilitating airway remodeling by increasing bronchial smooth muscle cell migration and proliferation [21], inducing airway hyperresponsiveness (AHR) [22], and stimulating epithelial-mesenchymal transition (EMT) [23] in the airways.