The role of neutrophils in allergic disease

Neutrophils are short-lived cells of the innate immune system and represent 50-70% of the circulating leucocytes. Their primary role is antimicrobial defence which they accomplish through rapid migration to sites of inflammation followed by phagocytosis, degranulation, and the release of neutrophil extracellular traps (NETosis). While previously considered terminally differentiated cells, they have been shown to have great adaptability and to play a role in conditions ranging from cancer to autoimmunity. This review focuses on their role in allergic disease. In particular: their role as potential amplifiers of type 1 hypersensitivity reactions leading to anaphylaxis; their involvement in alternative pathways of food and drug allergy; their role in allergic rhinitis and asthma and neutrophil dysfunction in atopic dermatitis. The use of potential biomarkers and therapeutic targets is also discussed with a view to guiding future research.