Effect of anti-IL5R therapy on nasal epithelial cell permeability in severe eosinophilic asthma

The airway epithelium in severe eosinophilic asthma (SEA) exhibits fragility, reduced integrity and increased epithelial permeability. The effect of blocking the IL-5Ra receptor on eosinophils, on epithelial barrier function in SEA remains unexplored. <bold>Aim:</bold> Characterise SEA patient nasal epithelial cells (NECs) to investigate barrier function, basal cell differentiation and how this is altered in response to anti-IL5Ra therapy, Benralizumab. Air-liquid interface (ALI) culture barrier permeability and integrity were measured using TEER and FITC-dextran assays in NECs pre-and after 1-and 6-months of Benralizumab. RNAseq, qRT-PCR and immunofluorescent imaging analyses compared expression levels of adhesion, tight junction, goblet, and ciliated cell genes (n=7 per time-point). Barrier integrity increased in SEA 6-months post Benralizumab (3.6-fold, p=0.03) with smaller changes after 1-month (fold-change 1.32). Barrier permeability reduced 4.39-fold after 6-months. Gene and protein expression of E-cadherin and claudin-1 increased after 1-and 6-months of therapy (1.91-fold-change, p=0.002; 8.55-fold change, p<0.001). Mucus produced by goblet cells in ALI reduced (2.2g reduction in weight), corresponding with decreased MUC5AC gene expression (1.74-fold less expression, p=0.008). Increased ciliated cell FoxJ1 gene expression was noted at 1-and 6-months of treatment (4.36-fold increase, p=0.006). Genes associated with IL-2 signalling, cell-adhesion and apical junctions were increased at 6-months of Benralizumab compared to baseline. Benralizumab alters barrier permeability, integrity, and basal cell differentiation of NECs by increasing the gene and protein expression at the cell tight junctions.