IgE, but not allergens, induces the release of neutrophil l u indd extracellular traps

Introduction: Neutrophils play an important role in innate immunity. To eliminate pathogens they use several mechanisms, such as phagocytosis, degranulation, production of reactive oxygen species (ROS), and release of neutrophil extracellular traps (NETs). It was recently shown that neutrophils can degranulate under the influence of immunoglobulin E (IgE) as they express receptors for IgE. The impact of IgE on the release of NETs has not been investigated thus far.Aim: To investigate if neutrophils can release NETs following IgE, anti-IgE or allergen stimulation. Material and methods: Neutrophils were isolated by gradient centrifugation from peripheral blood obtained from sensitized patients and healthy blood donors. Basophil activation was measured using flow cytometry. The presence of NETs following IgE, anti-IgE and allergen stimulation was evaluated quantitatively by fluorometry and qualitatively by fluorescent microscopy. Results: IgE stimulated NETs release in a concentration-dependent manner, causing the greatest release at 2.86 mu g/ml. NETs release under IgE stimulation was significantly stronger in allergic subjects comparing with non-allergic ones, and seemed to be independent of FcERI expression. IgE-dependent NETs release was significantly decreased following treatment with N-acetylcysteine and 4-aminobenzoic acid. Anti-IgE and allergens Conclusions: Neutrophils can release NETs in the presence of a high concentration of IgE, which appears to be partially dependent on the allergic status of the patient and the production of ROS. This finding may contribute to better understanding of inflammatory processes accompanied by atopic diseases.