Mucosa-associated lymphoid tissue
Mucosa-associated lymphoid tissue | |
---|---|
Details | |
System | Lymphatic system |
Identifiers | |
Acronym(s) | MALT 2 |
FMA | 62819 |
Anatomical terminology |
The mucosa-associated lymphoid tissue (MALT), also called mucosa-associated lymphatic tissue, is a diffuse system of small concentrations of
dendritic 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. Immune responses that occur at mucous membranes are studied by mucosal immunology
.
Categorization
The components of MALT are sometimes subdivided into the following:
- GALT (Peyer's patchesare 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)[1]
- LALT (larynx-associated lymphoid tissue)
- SALT (skin-associated lymphoid tissue)
- VALT (vulvo-vaginal-associated lymphoid tissue)
- TALT (testis-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.[2]
- 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.[2]
Role in disease
MALT plays a role in regulating mucosal
marginal zone B-cell lymphoma (a subtype of which is termed MALT lymphoma). Certain subtypes of marginal zone B cell lymphomas such as those occurring in the stomach are commonly caused by Helicobacter pylori infection.[3]
Peyer's Patches, groupings of lymphoid follicles in the mucus membrane, monitor the GALT closely to regulate pathogens that traverse through the area. Due to the function of M cells in Peyer's patches, involving the adherence and transport of antigens across a single layer of epithelial cells, dysfunction in these structures could allow an entry point to pathogens.
References
- PMID 22442734.
- ^ a b Gray's Anatomy, 38ed. p. 1442 ff.
- PMID 30364585.
External links
- MALT resource page - Patients Against Lymphoma
- Maltoma