Neutrophilic asthma at an inhibitory checkpoint: a PD-1 -targeted approach.

In this issue of the Journal of Allergy and Clinical Immunology, Helou et al1 provide compelling evidence that programmed cell death protein 1 (PD-1) plays a protective role in an established murine model of acute steroid-resistant neutrophilic asthma.2 Neutrophilic asthma models in mice serve to examine the mechanisms leading to “non–type 2” (non-T2) asthma, in which there is an absence of T2 features such as airway eosinophilia. Non-T2 asthma tends to be less responsive to corticosteroids, revealing a need to better understand the mechanism of potential alternative therapies against the immune response that leads to airway hyperresponsiveness (AHR).