IgE-positive mast cells on the human nasal mucosal surface in response to allergen exposure

IgE-bearing mediator cells are suggested to be the effector cells in type I allergic rhinitis. These cells can be demonstrated by their granular constituents or by the surface-bound IgE antibodies. We developed immunohistochemical techniques in order to stain the cell-bound IgE using polyclonal or monoclonal anti-human IgE antibodies. These techniques can be applied to nasal biopsies as shown previously or to cytospin specimen harvested by a brush method. They deliver excellent staining results with well-preserved morphological details. Brush samples were taken from 24 grass pollen allergic subjects before season, after a nasal allergen provocation and two weeks after the onset of season. There was a statistically significant increase in toluidine blue positive and IgE-positive cells 24 hours after nasal provocation (app. 12-fold, p less than 0.05) and more pronounced within the season (app. 58-fold, p less than 0.001) compared to preseasonal values. These cells appeared to be mast cells rather than blood basophils judged by morphological criteria. There was a striking correlation between the number of toluidine blue cells and that of IgE-positive cells (r = 0.98). The number of eosinophils also increased due to the seasonal allergen exposure (p less than 0.001), but less pronouncedly compared to the mast cells. These data re-emphasize the migration of IgE-bearing mast cells and eosinophils into the epithelial lining of the nasal mucosa due to allergen interaction and point to a possible role of mast cells as a carrier for IgE-molecules.