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November 25, 1992

The Immunopathogenesis of Gastrointestinal and Hepatobiliary Diseases

JAMA. 1992;268(20):2910-2917. doi:10.1001/jama.1992.03490200162019

THE MUCOSAL immune system is composed of afferent lymphoid tissues (the mucosal follicles, Peyer's patches) and efferent lymphoid tissues (the diffuse lymphoid tissues underlying the various epithelial surfaces of the gastrointestinal [GI], respiratory, and reproductive tracts and the lactating mammary gland), with several unique features that facilitate host defense at mucosal surfaces.1 One unique feature is the tendency of cells originating in the mucosal follicles to migrate to the diffuse lymphoid areas; such mucosa-specific "homing" is a mechanism of targeting cells induced by mucosal antigens to mucosal areas. Another unique feature of the mucosal immune system is that B cells in mucosal follicles tend to differentiate into cells that produce polymeric IgA, an immunoglobulin particularly suited to mucosal function. This is seen in the ability of IgA to use the polymeric immunoglobulin transport receptor on the surface of mucosal epithelial cells (secretory component) to gain ready access to the