Separately, emphysema was attenuated in IL-17A- and IL-17RA-deficient mice exposed to long-term cigarette smoke, compared to wild-type controls, and IL-1RI–dependent IL-17A was found to be critical for pulmonary neutrophilia in H. influenzae-induced acute exacerbation using the same model [117–119]. Here, IL17A is linked to pulmonary emphysema.