IL17A and asthma: To investigate this further, we classified the asthmatics as neutrophilic asthma, eosinophilic asthma, and paucigranulocytic asthma based on their phenotypes of airway inflammation, and found that the level of percentage of Th17 cells in peripheral Th cells, as well as the concentrations of IL-17 in sputum and the culture supernatant of activated PBMCs were significantly higher in children with neutrophilic asthma than those in children with eosinophilic and paucigranulocytic asthma, which indicated a predominance of Th17-mediated immunity in the pathogenesis of neutrophilic asthma.