The appendix, long misunderstood as a vestigial organ, is now recognized as a key MALT structure, playing an essential role in B-lymphocyte-mediated immune responses, hosting extrathymically derived T-lymphocytes, regulating pathogens through its lymphatic vessels, and potentially producing early defenses against diseases.
[1] In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and deliver it to the lymphoid tissue.
Immune responses that occur at mucous membranes are studied by mucosal immunology.
Certain subtypes of marginal zone B cell lymphomas such as those occurring in the stomach are commonly caused by Helicobacter pylori infection.
[4] Peyer's Patches, groupings of lymphoid follicles in the mucous membrane, monitor the GALT closely to regulate pathogens that traverse through the area.