Local IgE production in the nasal mucosa: a review.

IgE is one of the most important markers for allergy. The presence of specific IgE on skin mast cells (skin test) and/or the existence of specific IgE in serum (RAST) indicates sensitization, but not necessarily clinical allergy, in the target organ. Discrepancies between sensitization and disease could be explained by local IgE production. The nasal mucosa contains all the cell types necessary for a local IgE immune response. Moreover, it has been shown that this local IgE is specific for the specific allergen to which the patient is allergic. The availability of IL-4 and IL-13 produced in the nasal mucosa creates the possibility for isotype switching of B cells to IgE-positive B cells, and proliferation and maturation of B cells to IgE-producing plasma cells. The IgE positivity of B cells and plasma cells implies that IgE production occurs in the nasal mucosa. The observation of the presence of allergen-positive plasma cells and the finding that all allergen-positive cells were also IgE-positive indicates that this local IgE production is allergen-specific. Data discussed in this review provide strong evidence for the local production of specific IgE in the nasal mucosa.