60 <i>In vitro</i> models for respiratory allergic responses: a rapid review of current approaches and challenges

Abstract Allergic respiratory diseases are a growing global health concern, yet experimental studies continue to rely heavily on animal models that do not fully reflect human airway biology. In vitro epithelial models provide an opportunity to investigate mechanisms of allergic sensitisation and effector responses under controlled, human-relevant conditions. However, the range, reproducibility and translational value of current respiratory epithelial models remain uncertain. A rapid literature review was conducted to identify in vitro epithelial models used to study allergic sensitisation or effector mechanisms published between 2015 and 2025. Searches were performed in PubMed, Web of Science, Scopus and Google Scholar using combinations of MeSH and keyword terms for allergy, hypersensitivity, in vitro and model/assay. Studies were included if they described human or mammalian epithelial-based systems assessing endpoints such as cytokine or chemokine release (eg IL-6, IL-8, IL-33, TSLP), barrier integrity (eg TEER, tight-junction protein expression), or epithelial–immune signalling within co-culture designs following allergen exposure. Screening and data extraction are currently in progress. The review will chart model characteristics by cell type, culture format and exposure approach, and map commonly assessed biological endpoints. Synthesised findings will be used to highlight methodological gaps, identify emerging best practices, and support the development of more standardised and predictive airway models for respiratory allergy research and risk assessment. The work will also provide a reference framework for selecting or designing epithelial models that more accurately represent human airway responses to allergens and irritants, facilitating improved comparability, validation, and future mechanistic studies.