EOSINOPHILS AND IL-5 RECEPTOR IN COVID-19 POSTMORTEM LUNG TISSUE

ABSTRACT

TOPIC Chest Infections TYPE Original Investigations PURPOSE: Severe COVID-19 infections have been associated with alterations in blood eosinophil counts and elevated blood interleukin (IL)-5 levels [1,2]. The aim of this study was to explore whether eosinophils and IL-5 receptors are observed in post-mortem lung tissue from patients with COVID-19 pneumonia. METHODS: Hematoxylin & eosin (H&E) and immunohistochemical staining (major basic protein [MBP], eosinophil-derived neurotoxin [EDN], interleukin-5 receptor alpha [IL-5Rα] + neutrophil elastase duplex, IL-5Rα + tryptase duplex, and basophils [2D7]) were performed on post-mortem lung tissue samples from 10 patients with COVID-19 pneumonia, 5 patients with non-COVID-19 viral pneumonia, and 5 patients without pneumonia. RESULTS: Low to moderate numbers of eosinophils were identified in H&E-stained samples of post-mortem lung tissue from patients with COVID-19 and non-COVID-19 pneumonia. There was also moderate to marked immunohistochemical expression of IL-5Rα in both pneumonia groups, and some IL-5Rα–expressing cells also expressed neutrophil elastase. IL-5Rα expression did not generally colocalize with tryptase expression, but rare colocalization was also observed in all groups. CONCLUSIONS: Eosinophils and eosinophil activation products are present in COVID-19 lung disease, suggesting that eosinophils may play a role in the pathogenesis of viral pneumonias. Co-expression of IL-5Rα and neutrophil elastase suggests that, within pathological contexts including viral pneumonia, IL-5Ra-dependent processes may influence neutrophil function. CLINICAL IMPLICATIONS Eosinophil-depleting therapies such as benralizumab may be potential therapeutic agents for COVID-19 disease and other viral pneumonias. REFERENCEs 1. Lucas C, Wong P, Klein J, et al. Longitudinal analyses reveal immunological misfiring in severe COVID-19. Nature. 2020;584(7821)463–9. 2. Rodriguez L, Pekkarinen PT, Lakshmikanth T, et al. Systems-level immunomonitoring from acute to recovery phase of severe COVID-19. Cell Rep Med. 2020;1(5)100078. DISCLOSURES Employee relationship with AstraZeneca Please note 7.5 years Added 04/30/2021 by Jennifer Cann, source=Web Response, value=stock grants No relevant relationships by David Chain, source=Web Response Employee relationship with AstraZeneca Please note 15/06/2020 Added 04/30/2021 by Ron Chen, source=Web Response, value=Salary No relevant relationships by Karma Dacosta, source=Web Response No relevant relationships by Adrian Freeman, source=Web Response Employee relationship with AstraZeneca Please note 1996 to date Added 04/29/2021 by Andrew Jones, source=Web Response, value=Salary Stock Owner relationship with AstraZeneca Please note 1996 to date Added 04/29/2021 by Andrew Jones, source=Web Response, value=Stock Owner Employee relationship with astrazeneca Please note current Added 04/30/2021 by Rohit Katial, source=Web Response, value=Salary Employee relationship with AstraZeneca Please note July 2019-present Added 04/29/2021 by Allen McAlexander, source=Web Response, value=Salary Employee relationship with AstraZeneca Please note Jul 1999 to present Added 04/29/2021 by Christopher McCrae, source=Web Response, value=Salary Employee relationship with AstraZeneca Please note Jul 1999 to present Added 04/29/2021 by Christopher McCrae, source=Web Response, value=Ownership interest No relevant relationships by Hitesh Sanganee, source=Web Response No relevant relationships by WEIGUANG ZHAO, source=Web Response