ABSTRACT
In this study, we have attempted to summarize and clarify the concept of nasal permeability to antigens such as inhaled particles, bacterial breakdown products and medicaments. The mature epithelium retains the capacity to allow macromolecules to penetrate by a pinocytotic mechanism, which is more pronounced during the neonatal period. The vast majority of individuals have no ill effects from the nasal transport of large molecules. However, when increased quantities of toxic or antigenic macromolecules gain access to the body because of a derangement in the protective mucosal barriers (namely: the Secretory IgA (SIgA), the mucous plug with the cilia, the intracellular digestion or interstitial immunoglobulins and macrophages), antigen absorption may be altered and result in either local or systemic disorders. The speculative concepts suggesting that clinical disease-states (e.g. allergy, atrophic rhinitis, rhinoscleroma, infection and malignancy), may be associated with altered mucosal permeability have also been discussed.
