Wpływ środowiska wiejskiego na rozwój astmy i alergii u dzieci

Children who grow up on dairy farms rarely develop asthma or allergies. Researchers suspect a key reason is that the kids breathe in air full of lipopolysaccharides, molecules from the cell wall of bacteria G-, known as endotoxins. Endotoxin-reduced epithelial cell cytokines activate dendritic cells (DCs), thus suppressing type 2 immunity to house dust mites and reducing the overall reactivity of the immune system and later protecting children from asthma. Schuijs et al showed that an enzyme involved in this defense, called A20, is made by the epithelial cells. Loss of the ubiquitin-modifying enzyme A20 abolished the protective effect. Thus, the farming environment protects from allergy by modifying the communication between barrier epithelial cells and DCs through A20 induction. Their study offers new support for the hygiene hypothesis, which posits that zeal for cleanliness and widespread use of antibiotics have purged the environment of microorganisms that once taught a child's developing immune system not to overreact to foreign substances. This paper is a summary of up-to-date information on hygiene hypothesis. 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.