Single-cell platforms for the analysis of local airway responses to allergen challenge
Immunological mechanisms (English)Allergic responses to allergens are typically dominated by Th2 cells and allergen-specific IgE. Most knowledge on allergic immune responses is based on peripheral blood cells from allergic patients or from animal models. Information on tissue-specific responses is scarce, however allergen-specific immune responses are initiated locally and this information is crucial for the development of novel therapies. Nasal biopsies provide valuable information regarding the upper airway immune responses, however the number of cells obtained from these biopsies is a limiting factor. A recently developed technique, combining mass-spectrometry and cytometry (CyTOF) overcomes this limitation by measuring up to 42 phenotypical cell markers in one measurement. In this study nasal biopsies were taken from 15 allergic rhinitis subjects and 15 healthy controls, before and after nasal challenge with House Dust Mite allergen. The biopsies were digested and the cellular composition of the resulting single cell suspensions were measured by CyTOF. The heiraichal clustering analysis platform Cytosplore was used for visualisation and automated clustering of the data, resulting in 13 lineages of cells and a total of 207 clusters within the CD45+ population in nasal tissue. In accordance with their atopic status, allergic subjects could be distinguished from healthy controls based on increased FceRI expression levels on dendritic cells, monocytes and mast cells. Furthermore, a higher frequency of a specific monocyte population was present in healthy controls at baseline compared to allergic subjects. Upon allergen challenge an influx of granulocytes and specific monocyte populations into the nasal tissue was detected in allergic subjects only. The extensive CyTOF marker panel employed in this study allows for detailed phenotyping of these particular cell populations, providing key insights into the local cellular responses to allergen challenge in both allergic and healthy individuals.