Persistent IgE synthesis in the nasal mucosa of hay fever patients.

The location of IgE synthesis has been a longstanding controversy, with previous evidence favoring either the mucosa or lymphoid tissue in the region of allergen entry. The evidence for IgE synthesis in mucosal tissues has always been circumstantial. We have developed a novel explant culture system, using ELISA and radioactive amino acid incorporation, to measure de novo IgE protein synthesis in the nasal mucosa of hay fever patients. Surprisingly, IgE synthesis continues between seasons in the explants from grass pollen-sensitive patients and a higher proportion of this IgE compared to serum IgE is allergen specific. Persistent IgE synthesis may ensure the expression of immediate hypersensitivity in the mucosa and promote rapid amplification of the allergic response in the local lymphoid tissue on allergen provocation. Our work demonstrates definitively for the first time that the local mucosa is a site of ongoing IgE synthesis.

Local IgE production.

Recent data from a number of groups have confirmed that IgE antibody may be produced, at least in part, locally within the nasal mucosa. Our data support the theory that B cell switching may also occur locally, although this remains to be confirmed. Local IgE may account for local disease expression in atopic subjects, although it is not clear which step is rate-limiting in this process. Our results highlight the importance of developing local strategies targeted against IgE for treatment of allergic diseases.