IL17A and asthma: A study quantifying bronchial angiogenesis as well as the number of IL-17A cells and the concentration of angiogenic factors in sputum in subjects with severe asthma, COPD, and healthy subjects found that IL-17A enhances bronchial vascular remodeling by stimulating the synthesis of other angiogenic factors may lead to mucosal congestion resulting in airway narrowing (116).