Purpose of review: Allergies are a global health problem with rapidly increasing prevalence but still lacking pathogenetic knowledge or optimal treatment. The objective is to add to the conventional thinking that allergies are caused by overactive, mainly T-cell-mediated, immunological responses and thus to raise the putative role of altered epithelial functions.
Recent findings: Birch pollen allergen was rapidly and actively transported through the respiratory epithelium via caveolar-dependent mechanisms only in patients allergic to birch pollen but not their healthy controls. Transcriptomic analyses showed that whereas healthy individuals raised a strong epithelial response after intranasal allergen challenge, the allergic patients had a reduced response. Thus allergies could also be due to hyporeactive responses on the epithelial level.
Summary: Epithelium has emerged as an active and complex organ with mechanical, biochemical and immunological functions. The increasing awareness that epithelium interacts actively with allergens might provide new targets for the prevention and management of allergy.