Effect of benralizumab on the levels of bronchial epithelial-produced alarmins, collectins and mucosal-associated chemokine CCL28 in the blood of patients with severe eosinophilic asthma

<bold>Background:</bold> Benralizumab is an effective drug targeting the interleukin (IL) 5 receptor in patients with severe eosinophilic asthma (SEA). It eliminates circulating blood eosinophils, and significantly reduces their presence in lung tissue, bronchial secretions. Therefore, it is likely that benralizumab indirectly affects alarmins, collectins and mucocal-associated chemokines production in SEA. <bold>Aim:</bold> To evaluate the effect of benralizumab on the levels of alarmins (IL-25, IL-33, thymic stromal lymphopoietin (TSLP)), collectins (surfactant protein A1 and D (SPA1, SP-D)), chemokine (C-C motif) ligand 28 (CCL28) in the blood and to assess associations with clinical features (forced expiratory volume in 1 second (FEV₁), asthma control test (ACT) score) in patients with SEA. <bold>Methods:</bold> We examined 13 SEA before and 4 weeks after subcutaneous administration of benralizumab 30 mg, and 14 healthy individuals. Serum substances levels were measured by enzyme-linked immunosorbent assay. <bold>Results:</bold> In patients with SEA, a single dose of benralizumab significantly reduced blood levels of IL-33 (from 42.48±4.90 to 38.71±3.48 pg/ml, p=0.013), TSLP (95.75±105.24 <italic>vs</italic> 82.70±102.34 pg/ml, p=0.002), and CCL28 (260.21±185.45 <italic>vs</italic> 164.05±66.09 pg/ml, p=0.003) to the level of healthy individuals, while IL-25, SPA1, SP-D levels remained unchanged. Changes in substances levels did not correlated with changes in FEV₁ and ACT. <bold>Conclusion:</bold> A single dose of benralizumab diminished blood levels of IL-33, TSLP, and CCL28 in patients with SEA, but these changes were not associated with increases in FEV₁ values and ACT scores.