Mucosal immunity in allergic rhinitis.

Secretory IgA (SIgA) is the main agent protecting the mucosal districts against both infectious microorganisms and inert foreign macromolecules. A lack of secretory immunity has previously been described in patients with allergic rhinitis, but it is a controversial finding. The discrepant results of SIgA levels found in allergy may partially be due to methodological problems. Sixty patients with previously demonstrated allergic rhinitis, treated or not with specific desensitization therapy and free from clinical manifestation of rhinitis were studied. Normal volunteers and patients with selective 11S IgA deficit, without allergic pathology, were investigated as controls. The titration of SIgA in nasal secretions, performed by an original immunoisoelectro-focusing method, showed significantly decreased values in allergic patients. An evaluation of the IgE level in nasal secretion was performed by ELISA. Low rates of IgE were also found in the intercritic period.