Eosinophil granulocytes in chronic inflammatory respiratory diseases and CRSwNP: Function, immunological basis, and clinical significance.

INTRODUCTION:Eosinophils play an important regulatory and immunomodulatory role in airway mucosa and have antiparasitic and antiviral properties as well as pro-inflammatory effects that may also cause persistence of inflammation with tissue remodeling. The number of eosinophils and the detection of specific mediators in biological samples from, e.g., blood, nasal secretions, and bronchial fluid can serve as biomarkers that reflect the underlying pathophysiology of certain diseases, predict treatment success, and detect therapy effects. MATERIALS AND METHODS:A literature search was conducted to determine the immunologic basis, mode of action, clinical significance, and available evidence for therapeutic approaches using eosinophil-targeted monoclonal antibodies by searching Medline, Pubmed, and the national and international trial database (ClinicalTrials.gov) and guideline registries as well as the Cochrane Library. Human studies published on the topic in the period up to and including 10/2023 were considered. RESULTS:Based on the international literature and previous experience, the results are summarized, and recommendations are given. CONCLUSION:The important role of eosinophils in immunological processes in the airway mucosa is comprehensively analyzed and can serve as a basis for current and future treatment approaches.