The mucosal-associated lymphoid tissues of the upper respiratory tract, including adenoids
and palatine tonsils, are considered as the first line of defense against respiratory infections, being
important effector organs in both mucosal-type and systemic-type adaptive immunity. They are
strategically located for mediating both local and regional immune functions, as they are exposed to
antigens from both the inhaled air (allergens and pathogens) and the alimentary tract. Adenoids play
a major role in the early and effective immune responses against viral and bacterial upper airway
infections, as well as in the development of allergic reactions to respiratory allergens, being
influenced by several environmental antigens and pollutants, such as tobacco smoke. In addition,
recent studies have focused on new immune-modulating strategies for adenoidal cells as a preventive
and therapeutic approach for chronic upper airways inflammation.
Herein, we aimed to summarize what is known about the cellular and molecular mechanisms
regulating adenoidal immune responses in the context of inflammation and allergy, with particular
reference to scientific literature published within the last five years.