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.

There are three types of situations in which MALT is present- Tonsils, Appendix, Small Intestinal area

Categorization

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)^[1]
• 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.^[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 immunity. It may be the site of lymphoma, usually non-Hodgkin lymphoma. A specific entity is the MALT lymphoma linked to Helicobacter pylori in the stomach.

References

External links

• MALT resource page - Patients Against Lymphoma
• Maltoma