The effect of inhaled corticosteroids on airway mast cells in type 2 low asthma

Abstract

Background: Mast cells play a key role in airway hyperresponsiveness (AHR) in asthma but infiltration of airway mast cells and the effect of inhaled corticosteroids (ICS) across Type 2 high (T2-high) and T2-low disease have only been poorly described. Aims and Objectives: To study the effect of inhaled corticosteroids (ICS) on airway mast cell density and phenotypes in patients with T2-high and T2-low asthma. Methods: The RECONSTRUCT-study was a prospective intervention study with 50 steroid-free patients with asthma stratified into T2-high (FeNO≥25 ppb) and T2-low (FeNO Results: MCT density was higher in T2-low asthma: Median: 0.20% (IQR: 0.18) than in T2-high asthma: 0.09% (IQR: 0.16), P=0.025. In comparison, MCTC density was higher in T2-high asthma: 0.39% (IQR: 0.30) than T2-low asthma: 0.17% (IQR: 0.09), p Conclusion: T2-low asthma is characterized by an MCT-predominant mast cell infiltration, whereas T2-high asthma is characterized by a higher density of MCTC. ICS decreases mast cell density in T2-high and T2-low asthma, suggesting infiltrating mast cells to be steroid-sensitive disease drivers in T2-low asthma.