Effector Cell Signature in Peripheral blood following Nasal Allergen Challenge in Grass Pollen Allergic Individuals.

BACKGROUND:

Several studies have demonstrated the time-course of inflammatory mediators in nasal fluids following nasal allergen challenge (NAC), whereas the effects of NAC on cells in the periphery are unknown. We examined the time-course of effector cell markers (for basophils, dendritic cells and T cells) in peripheral blood after nasal grass pollen allergen challenge.

METHODS:

Twelve participants with seasonal allergic rhinitis underwent a control (diluent) challenge followed by NAC after an interval of 14 days. Nasal symptoms and peak nasal inspiratory flow were recorded along with peripheral basophil, T cell and dendritic cell responses (flow cytometry), T cell proliferative responses (thymidine incorporation) and cytokine expression (FluoroSpot assay).

RESULTS:

Robust increases in nasal symptoms and decreases in PNIF were observed during the early (0-1h) response and modest significant changes during the late (1-24h) response. Sequential peaks in peripheral blood basophil activation markers were observed (CD107a at 3h, CD63 at 6h and CD203c^bright at 24h. T effector/memory cells (CD4⁺ CD25^lo ) were increased at 6h and accompanied by increases in CD80⁺ and CD86⁺ plasmacytoid DCs (pDCs). Ex vivo grass antigen-driven T cell proliferative responses and the frequency of IL-4⁺ CD4⁺ T cells were significantly increased at 6h after NAC when compared to the control day.

CONCLUSION:

Basophil, T-cell, dendritic cell activation, increased frequency of allergen-driven IL-4⁺ CD4⁺ T cells and T cell proliferative responses are detectable in the periphery after nasal allergen challenge. These data confirm systemic cellular activation following a local nasal provocation. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.