Mucosa-associated lymphoid tissue
|Mucosa-associated lymphoid tissue|
The mucosa-associated lymphoid tissue (MALT), also called mucosa-associated lymphatic tissue, is a diffuse system of small concentrations of lymphoid tissue found in various submucosal membrane sites of the body, such as the gastrointestinal tract, oral passage, nasopharyngeal tract, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and deliver it to the lymphoid tissue.
MALT constitute about 50% of the lymphoid tissue in human body.
The components of MALT are sometimes subdivided into the following:
- GALT (gut-associated lymphoid tissue. Peyer's patches are a component of GALT found in the lining of the small intestines.)
- BALT (bronchus-associated lymphoid tissue)
- NALT (nasal-associated lymphoid tissue)
- CALT (conjunctival-associated lymphoid tissue)
- LALT (larynx-associated lymphoid tissue)
- SALT (skin-associated lymphoid tissue)
- VALT (vulvo-vaginal-associated lymphoid tissue)
It can be also distinguished by level of organization of the tissue:
- O-MALT (organized mucosa-associated lymphatic tissue); specifically, the tonsils of Waldeyer's tonsillar ring are O-MALT.
- D-MALT (diffuse mucosa-associated lymphatic tissue); MALT that is not organized as a separately macroscopically anatomically identifiable mass, tissue or organ (such as the aforementioned O-MALT) is diffuse MALT.
Role in disease
- Hong Liang; Christophe Baudouin; Antoine Labbe; Luisa Riancho; Françoise Brignole-Baudouin (2012). "Conjunctiva-associated lymphoid tissue (CALT) reactions to antiglaucoma prostaglandins with or without BAK-preservative in rabbit acute toxicity study". PLoS One. 7 (3): e33913. doi:10.1371/journal.pone.0033913. PMC 3307783. PMID 22442734.
- Gray's Anatomy, 38ed. p. 1442 ff.