The effect of fluticasone propionate aqueous nasal spray on nasal mucosal inflammation in perennial allergic rhinitis.

Mast cell degranulation, and the subsequent recruitment of infiltrating inflammatory cells, such as eosinophils, into the nasal mucosa has long been considered the most important model to explain allergic rhinitis. Several studies show a decrease in the number of eosinophils and possibly also mast cells during local corticosteroid treatment. Over the last decade, a new model to explain allergic inflammation has evolved. In this model, Langerhans' cells and T-cells play an important role. Langerhans' cells possess a high affinity receptor for IgE. In patients with allergic rhinitis, allergen provocation results in stimulation of T-cells by the IgE-positive Langerhans' cells. The T-cells produce a number of cytokines which stimulate IgE production as well as the inflammatory reaction. The number of T-cells is not usually influenced by corticosteroid treatment; however, the function of the T-cells, shown by the spectrum of cytokines produced, is clearly influenced. The cells that are most dramatically affected by local corticosteroid treatment are the Langerhans' cells, which completely disappear during treatment. This decrease suggests that there is a reduction in antigen presentation. The subsequent decrease in T-cell stimulation may result in a reduction of the reactions that are dependent on T-cell-derived mediators.