Mucosal Immunity in Primary Immunodeficiencies

The epithelia covering the gastrointestinal, respiratory, urogenital, conjunctiva, and inner ear are integral parts of the immune system. Through mechanical and chemical means, they prevent invasion by pathogens. The mucosal immune system consists of an innate and acquired system that interact with each other in a complex way. The mucosal immune system also has the delicate task of differentiating between pathogens and non-pathogens. The T and B lymphocytes present in the mucous membranes are specific to these sites, differing from those we can find in the peripheral circle, and produce specific responses, such as local IgA secretion. In this chapter, we will discuss in a non-exhaustive way the main components and mechanisms of innate and adaptive mucosal immunity and how this can be compromised in primary immunodeficiencies.