Infiltration Pattern of Gammadelta T Cells and Its Association with Local Inflammatory Response in the Nasal Mucosa of Patients with Allergic Rhinitis

Background: gammadelta (γδ) T cells play important roles in allergic lower airway inflammation. However, little is known about their infiltration pattern in the nasal mucosa during upper airway inflammation. This study investigated γδ T cell distribution in nasal tissues of allergic rhinitis (AR) patients and the relationship between γδ T cells and other inflammatory cell types.

Methods: A total of 30 patients with septal deviation were examined, including 22 with and 8 without AR. The localization of γδ T cells and other cells (eosinophils, neutrophils, mast cells, macrophages, B cells, cluster of differentiation [CD]4+ T cells, CD8+ T cells, regulatory T cells [Tregs], interferon [IFN]-γ+ cells, interleukin [IL]17+ cells, and IL10+ cells) was evaluated by histological analysis and immunohistochemistry. T helper cell (Th)1/Th2/Th17 and Treg gene expression was analyzed by quantitative polymerase chain reaction (PCR).

Results: γδ T cells were localized in the epithelium or subepithelial region of nasal mucosa, and their infiltration was higher in AR patients relative to control subjects. The number of γδ T cells was associated with the presence of eosinophils, macrophages, mast cells, B cells, CD8+ T cells, Forkhead box (Fox)p3+ Tregs, IL17+ cells, and IL10+ cells but not of neutrophils or IFN-γ+ cells. The messenger RNA (mRNA) level of a γδ T cell subunit was positively correlated with those of Th1 genes (T-bet and IFN-γ), Th2 cytokine (C-C motif chemokine ligand 18), and Treg genes (Foxp3 and IL10).

Conclusion: γδ T cells play multiple roles in mucosal inflammation in AR including immune surveillance and adaptive and innate immune responses.