IL17A and asthma: Elevated levels of IL-17A have been reported in sputum, bronchoalveolar lavage (BAL) fluid, and peripheral blood8, 9, 10, 11 in those with severe asthma and have been implicated in pathogenesis.10, 12 In contrast, little is known about the role of neutrophils and the IL-17 pathway in children with STRA.