FcεRI-Toll-like receptor interaction in atopic dermatitis.

Exogenous factors such as allergens and microbial components play an important role as triggers of atopic dermatitis (AD). According to the current disease model, allergens as well as microbial antigens get into contact with surface receptors expressed by dendritic cells (DCs) in the skin of patients with AD. Allergen binding is most likely by the high-affinity receptor for IgE (FcεRI), which is highly expressed by epidermal DCs in AD. Beyond, pattern recognition receptors such as Toll-like receptors (TLRs) sense the environment for pathogen-associated molecular patterns. Combined stimulation of both receptor types by allergens and microbial antigens in the cellular micro-environment occurs frequently in AD. Modifications in the gene regions encoding those receptors as well as the pattern of DCs in the skin, the influence of the micro-environment together with the nature of incoming signals determine the type of immune response induced by FcεRI-and TLR-bearing DCs.