IL17A and asthma: In addition, severe asthma phenotypes may be associated with the presence of Th17 cells, and the production of a Th17 profile (IL-17A, IL-17 F, IL-22, and IL-21) and IL-1β, which was shown to induce a Th17 profile and induces an increase in airway inflammation predominantly within neutrophil cells [17, 18].