Alarmins Modulate Airway Contraction and Relaxation of Human Small Airways

To the Editor:Alarmins, including Thymic Stromal Lymphopoietin (TSLP) and Interleukins 33 and 25 (IL-33 and IL-25), contribute to the pathophysiology of allergic and nonallergic asthma while exacerbating the disease in response to allergens, viruses, and environmental irritants (as reviewed in 1 ).Current evidence shows that inhibiting alarmins reduces symptoms and exacerbations in obstructive lung diseases, including asthma 1 .Preclinical work has largely focused on alarmins' role in modulating airway inflammation, but far less is known about how alarmins regulate airway tone (contraction and relaxation).We posit that IL-33, TSLP, and IL-25 exert distinct effects on airway contraction and relaxation.