Mucosa-associated lymphoid tissue

"MALT" redirects here. For germinated cereal grains, see Malt.

The mucosa-associated lymphoid tissue (MALT) (also called mucosa-associated lymphatic tissue) is the diffusion system of small concentrations of lymphoid tissue found in various sites of the body, such as the gastrointestinal 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.

Categorisation

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]
• 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.^[3]

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

1. ^ Hong Liang, Christophe Baudouin, Antoine Labbe, Luisa Riancho, Françoise Brignole-Baudouin. Conjunctiva-Associated Lymphoid Tissue (CALT) Reactions to Antiglaucoma Prostaglandins with or without BAK-Preservative in Rabbit Acute Toxicity Study. PLoS One. 2012; 7(3): e33913. Published online 2012 March 19. doi: 10.1371/journal.pone.0033913
2. ^ Gray's Anatomy, 38ed. p. 1442 ff.
3. ^ ibid.

External links

• MALT resource page - Patients Against Lymphoma
• Maltoma

v t e Lymphoid system (TA A13.1–2, TH H3.10, GA 8 and 9) Primary lymphoid organs Bone marrow Hematopoietic stem cell Thymus Cortex Medulla Hassall's corpuscles Secondary lymphoid organs Spleen (process blood) structural: Hilum Trabeculae Diaphragmatic surface of spleen Visceral surface of spleen Red pulp Cords of Billroth Marginal zone White pulp Periarteriolar lymphoid sheaths Germinal center blood flow: Trabecular arteries Trabecular veins Tonsils/Waldeyer's tonsillar ring Palatine Lingual Pharyngeal Tubal Tonsillar crypts Lymph nodes (process extracellular fluid) lymph flow: Afferent lymph vessels Cortical sinuses Medullary sinuses Efferent lymph vessels T cells: High endothelial venules B cells: Primary follicle/Germinal center Mantle zone Marginal zone layers: Capsule/Trabeculae Subcapsular sinus Cortex Paracortex Medulla (Medullary cord) Hilum MALT (process mucosa) GALT Peyer's patch Germinal center M: LMO anat (h, u, t, a, l)/phys/devp noco/cong/tumr proc