IL17A and chronic obstructive pulmonary disease: 16HBE cells treated with tiotropium and 16HBE cells stimulated with ISs from COPD subjects treated with anti-IL-17A showed significantly lower levels of TSLP mRNA compared with cells stimulated with ISs from COPD patients (p < 0.0001 and p < 0.0001, respectively) (Fig. 3d).