Restoring the Airway Barrier: How Targeting Eosinophilic Inflammation Shapes Epithelial Health and Clinical Remission in Asthma

Asthma is a heterogeneous chronic airway disease in which eosinophilic inflammation represents a major type 2 endotype. The airway epithelium plays a central role in disease pathobiology by regulating barrier integrity, immune signaling, and tissue repair. In eosinophilic asthma, interactions between eosinophils and epithelial cells are associated with epithelial barrier disruption, altered differentiation, mucus hypersecretion, and airway remodeling. This review summarizes current evidence on the role of eosinophils in epithelial dysfunction and discusses biomarkers of epithelial injury, including epithelial-derived alarmins, chemokines, secretory proteins, and structural junctional markers. These biomarkers reflect different aspects of epithelial activation, injury, and repair and may contribute to improved characterization of disease mechanisms and inflammatory endotypes. The effects of biologic therapies targeting eosinophilic inflammation are also reviewed. While these treatments are associated with improved clinical outcomes and reduced eosinophil levels, available evidence indicates that epithelial alterations and remodeling processes may persist despite treatment. Overall, integrating epithelial biomarkers with clinical and inflammatory parameters may provide additional insight into disease activity and support more comprehensive assessment of asthma beyond conventional measures.