Allergen-encoded signals that control allergic responses

PURPOSE OF REVIEW: The purpose is to review the important recent advances made in how innate immune cells, microbes, and the environment contribute to the expression of allergic disease, emphasizing the allergen-related signals that drive allergic responses. RECENT FINDINGS: The last few years have seen crucial advances in how innate immune cells such as innate lymphoid cells group 2 and airway epithelial cells and related molecular pathways through organismal proteinases and innate immune cytokines, such as thymic stromal lymphopoietin, IL-25, and IL-33 contribute to allergy and asthma. Simultaneously with these advances, important progress has been made in our understanding of how the environment, and especially pathogenic organisms, such as bacteria, viruses, helminths, and especially fungi derived from the natural and built environments, either promote or inhibit allergic inflammation and disease. Of specific interest are how lipopolysaccharide mediates its antiallergic effect through the ubiquitin modifying factor A20 and the antiallergic activity of both helminths and protozoa. SUMMARY: Innate immune cells and molecular pathways, often activated by allergen-derived proteinases acting on airway epithelium and macrophages as well as additional unknown factors, are essential to the expression of allergic inflammation and disease. These findings suggest numerous future research opportunities and new opportunities for therapeutic intervention in allergic disease.