The central role of the epithelium in immune and inflammatory responses in the airways

New studies indicate that airway epithelial cells are equipped to recognize pathogen-associated molecular patterns via Toll-like receptors. When activated through these receptors, they produce cytokines, chemokines, and host defense effector molecules, suggesting a role in innate immune responses. Epithelial cells have been known to participate in airway inflammatory responses for many years. The recent demonstration that they express major histocompatibility and costimulatory molecules leads to the suggestion that epithelial cells may also act to locally coordinate adaptive immune responses in the airways.