Mucosal Immunity in Primary Immunodeficiencies

The epithelia that cover the gastrointestinal, respiratory, urogenital, conjunctiva, and inner ear play integral roles in the immune system’s defense mechanisms. Employing both mechanical and chemical barriers, these epithelia effectively prevent the invasion of pathogens. The mucosal immune system, encompassing both innate and acquired components, engages in intricate interactions. Its intricate task involves distinguishing between pathogens and non-pathogens. T and B lymphocytes present in the mucous membranes are site-specific, distinct from those in the peripheral circulation, and orchestrate specialized responses, including local IgA secretion. This chapter provides a non-exhaustive exploration of the primary components and mechanisms governing innate and adaptive mucosal immunity, along with insights into how these processes may be compromised in cases of primary immunodeficiencies.