PHENOTYPIC AND MOLECULAR CHARACTERISTICS OF NASAL MUCOSAL GAMMA-DELTAT-CELLS IN ALLERGIC AND INFECTIOUS RHINITIS

T cells expressing the T-cell receptor (TCR) gamma delta home in on va rious epithelia and may play an important role in local immunity to fo reign antigens. The nasal mucosa is a potential site for chronic infla mmatory diseases, yet little is known about the characteristics of nas al mucosal gamma delta T cells. Using flow cytometry, immunohistochemi stry, and RT-PCR, we elucidated the characteristics of nasal mucosal g amma delta T cells in patients with perennial allergic rhinitis (PAR), chronic infective rhinitis (CIR), and seasonal allergic rhinitis (SAR ) and in normal subjects. The gamma delta T cells were significantly i ncreased in the nasal mucosa of patients with PAR (PAR, 24.3 +/- 4.5%; CIR 12.9 +/- 2.7%, p < 0.01), unrelated to those in autologous periph eral blood (PAR, 5.6 +/- 0.8%; CIR, 9.6 +/- 2.8%), and they were prefe rentially distributed in the epithelial compartment (26.7 +/- 2.3%) ra ther than in the lamina propria (5.4 +/- 2.5%). Of the expanded popula tion of nasal mucosal gamma delta T cells in patients with PAR, CD4+ a nd CD4-8-gamma delta T cells were selectively increased (p < 0.01). Al though nasal intraepithelial gamma delta T cells from all groups of pa tients and normal subjects dominantly expressed the V gamma 1/V delta 1 genes, and a bias for V gamma 3 gene expression was noted in those o f patients with PAR, a significantly larger fraction of nasal mucosal gamma delta T cells in patients with PAR expressed the V gamma 1/V del ta 1 TCR (p < 0.01), whereas those of the peripheral blood expressed t he V gamma 2/V delta 2 TCR. More than 60% of V gamma 1/V delta 1 TCRcells in patients with PAR, were CD45RO+ (''memory cells''), independe nt of those in their peripheral blood (p < 0.01). Furthermore, a subst antial proportion of nasal mucosal gamma delta T cells in patients wit h PAR synthesized IL-4 and IL-5 but negligible amounts of IFN-gamma. T hese observations of an increase in the proportions and activation of distinct subsets of nasal mucosal gamma delta T cells and their Th2-ty pe cytokine profile in patients with PAR, unrelated to those in autolo gous peripheral blood suggest an important role for the oligoclonally expanded nasal mucosal gamma delta T cells in the pathogenesis of PAR.